Oh noes teh sky is falling!

[Vilya]

The only recordable optical media that I have ever had fail on me were early Philips discs. I have several burned discs, from other brands, pushing 20 years-old now that still play fine.

I have CDs that are 39 years-old that still work. I estimate my lifetime optical disc failure rate at about 0.5% ... and that's even when I include laserdiscs.

[Wendell R. Breland]

Originally Posted by Vilya

I have used alcohol to clean optical discs for decades without any ill consequences.

Really don't recall using alcohol on disc but it was the preferred cleaner for tape machine heads, pinch rollers, etc. 99.9% Isopropyl Alcohol was what we used at work. I buy this one for my use.

[JurassicBD]

Originally Posted by Vilya

I have used alcohol to clean optical discs for decades without any ill consequences. If I was destroying discs left and right, I would have stopped using alcohol ages ago. I only use it when simpler cleaning methods fail. I am not soaking the discs in it, just applying a little to the playback surface, wipe with microfiber cloth, rinse with water, and dry with another microfiber cloth. Total contact time with alcohol is mere seconds.

The cloudy milky white residue that I sometimes find on DVDs is not simple "case film" or that oily ooze that smears with the slightest touch; it does not come off at all unless I use alcohol; I have saved many an old DVD this way.

Thanks for sharing that. I've honestly never tried alcohol on a disc. I've used it to clean cases before though and it's proven quite effective at removing adhesive residue, at least stuff that's still tacky. But I've read industry papers that specifically said not to use it or any cleaner that contained alcohol on discs. Sounds like you've been very delicate with your applications and may have avoided contact with the edges. It also sounds like the notion that it'll damage the hardcoat may be unfounded. It's still something I wouldn't risk, but anything I've ever come across that baby shampoo or mild hand-soap wouldn't remove, I returned. It's been very rare that I needed anything more than a dry microfiber cloth. I apparently haven't come across the white residue you're referring to.

Originally Posted by kfbkfb

A few decades ago, Philips was asked about (stamped) CD lifetimes, they cleverly stated that the typical (stamped) CD would last 1000 years, but in the case of a poor storage environment, that number would be reduced by a factor of 20 to 50 (meaning 20 years worst case).

I have had a few Philips manufactured (a certain one of their CD factories) CD Videos fail, the (analog) LaserDisc format video has progressively more static and the PCM/CD format digital audio error correction eventually can't fix the disc deterioration.

I had 1 Blu-ray fail (depends on player, some won't start to play it, others will play just the beginning then stop) and no DVDs fail.


Kirk Bayne

I bought many hundreds of cds back in the late 80's and 90's myself, many from music clubs. And for years, they were kept in a fairly humid environment, as we live in the humid south, didn't have a/c yet, and even used oil heat in the winter which was a more moist heat. About a year ago, I copied every single one to the computer, to transfer to a tablet, for playback on an ION bluetooth speaker at the shop - its like all the radio stations I listen to coordinate their commercials at the exact same time, and radio spots are even more obnoxious today than they used to be. I am happy to report that not a single cd was defective. And they were used pretty heavily with all the traveling I did in the 90's, often sitting in a hot car or truck parked for hours in the summer sun. They certainly were used and abused a LOT more so than how we treat movies.

Out of thousands of dvds, we've had VERY few go bad, though I should qualify that by saying we started selling off our dvds in 2006, as we replaced them with BD, so aside from the relative few we still own, most weren't in our collection anywhere near as long as the cds we still have. Even ones that had widespread defective early pressings, I always lucked up.

It's still too early to qualify UHDs reliability, though one can reasonably assume UHD BD will prove similar to HD BD, which in my experience, while still overwhelmingly dependable, despite supposedly being even more durable than dvd, have been significantly more problematic. I've had dozens of bds either arrive defective, have player specific issues, or develop oxidation within a few years, and I fear the later percentage may increase as production standards have clearly, seemingly sharply, declined. And UHD has already shown to be very problematic for some player brands. I assume there are too few replicators to handle demand. But it might also have something to do with how the discs are pressed overseas and shipped to the US where they're packaged. I don't know how they're shipped, but that may be where a lot of the scratches are coming from, that or handling during final assembly, rather than from poorly maintained, over-stressed replication equipment itself.

[JurassicBD]

Originally Posted by Wendell R. Breland

Really don't recall using alcohol on disc but it was the preferred cleaner for tape machine heads, pinch rollers, etc. 99.9% Isopropyl Alcohol was what we used at work. I buy this one for my use.

It's also ideal for projector and other glass optics, as it drys fast and doesn't leave a film behind.

[Vilya]

Originally Posted by JurassicBD

Thanks for sharing that. I've honestly never tried alcohol on a disc. I've used it to clean cases before though and it's proven quite effective at removing adhesive residue, at least stuff that's still tacky. But I've read industry papers that specifically said not to use it or any cleaner that contained alcohol on discs. Sounds like you've been very delicate with your applications and may have avoided contact with the edges. It also sounds like the notion that it'll damage the hardcoat may be unfounded. It's still something I wouldn't risk, but anything I've ever come across that baby shampoo or mild hand-soap wouldn't remove, I returned. It's been very rare that I needed anything more than a dry microfiber cloth. I apparently haven't come across the white residue you're referring to.

I have been buying and using optical media for nearly 40 years and my experience has shown that cleaning a disc with a little isopropyl alcohol can save an otherwise unsalvageable disc.

If other cleaning methods fail, there isn't exactly much to lose by using alcohol, is there? I have found it to be quite effective at removing this cloudy white fog, or haze, that seems "baked" on in that it does not smear to the touch nor will soap and water budge it. This discoloration looks like "frozen" white smoke, uneven in its appearance, and it sorta reminds me of how car headlight lenses look after they go from clear to semi-opaque. I have only seen this occur with DVDs and usually those stored in white plastic or translucent cases.

Returning a disc isn't always an option, especially if the uncooperative disc is now long out of print or if the exchange period has passed. I have been able to save a few otherwise unplayable discs this way.

[Vilya]

Originally Posted by JurassicBD

It's still too early to qualify UHDs reliability, though one can reasonably assume UHD BD will prove similar to HD BD

[Show spoiler], which in my experience, while still overwhelmingly dependable, despite supposedly being even more durable than dvd, have been significantly more problematic. I've had dozens of bds either arrive defective, have player specific issues, or develop oxidation within a few years, and I fear the later percentage may increase as production standards have clearly, seemingly sharply, declined. And UHD has already shown to be very problematic for some player brands. I assume there are too few replicators to handle demand. But it might also have something to do with how the discs are pressed overseas and shipped to the US where they're packaged. I don't know how they're shipped, but that may be where a lot of the scratches are coming from, that or handling during final assembly, rather than from poorly maintained, over-stressed replication equipment itself.

There were some manufacturing errors that caused some early blu-rays to prematurely fail. Several Lionsgate releases from around 2008-2009 and Criterion discs made around 2011 had very high failure rates; the latter due to bronzing.

When a blu-ray is correctly manufactured and reaches us unscathed from crappy packaging and ham-handed shipping, they have proven to be very reliable. I have had extremely few blu-rays fail over the past 15 years and those that did were almost entirely early Lionsgate discs or 2011 Criterion discs.

4K discs have much higher data density than blu-rays making them far more prone to reading errors. A smudge or slight scratch that would not hinder blu-ray playback can stop a 4K disc dead in its tracks. A properly pressed, packaged, handled, and stored 4K disc should enjoy a long life span similar to that of a blu-ray, but just remember that the higher data density of a 4K disc makes it far less forgiving of any imperfections.

[Vilya]

Originally Posted by Wendell R. Breland

Really don't recall using alcohol on disc but it was the preferred cleaner for tape machine heads, pinch rollers, etc. 99.9% Isopropyl Alcohol was what we used at work. I buy this one for my use.

I don't perform surgery, so I think that 99.9% medical grade isopropyl alcohol would be overkill, and much more expensive, for cleaning a DVD. The buck a bottle 70% variety more than does the job here.

[Wendell R. Breland]

Originally Posted by Vilya

I don't perform surgery, so I think that 99.9% medical grade isopropyl alcohol would be overkill, and much more expensive, for cleaning a DVD. The buck a bottle 70% variety more than does the job here.

But many/most of those contain water, denaturants, and perfume oils. Remember I still have a D-VHS machine and have to clean the video heads and tape path, the rubbing variety of alcohol should not be used here. Same for rubber and plastic rollers for laser and inkjet printers.

[Vilya]

Originally Posted by Wendell R. Breland

But many/most of those contain water, denaturants, and perfume oils. Remember I still have a D-VHS machine and have to clean the video heads and tape path, the rubbing variety of alcohol should not be used here. Same for rubber and plastic rollers for laser and inkjet printers.

I can definitely understand your need for it, but to clean a disc? Nope.

I don't clean discs with cologne or aftershave, either, so other than those I don't know where you're finding perfume oils in rubbing alcohol. I have bought many a bottle of 70% and 91% isopropyl alcohol and the only inactive ingredient in what I buy is water.

[JurassicBD]

Originally Posted by Vilya

I have been buying and using optical media for nearly 40 years and my experience has shown that cleaning a disc with a little isopropyl alcohol can save an otherwise unsalvageable disc.

If other cleaning methods fail, there isn't exactly much to lose by using alcohol, is there? I have found it to be quite effective at removing this cloudy white fog, or haze, that seems "baked" on in that it does not smear to the touch nor will soap and water budge it. This discoloration looks like "frozen" white smoke, uneven in its appearance, and it sorta reminds me of how car headlight lenses look after they go from clear to semi-opaque. I have only seen this occur with DVDs and usually those stored in white plastic or translucent cases.

Returning a disc isn't always an option, especially if the uncooperative disc is now long out of print or if the exchange period has passed. I have been able to save a few otherwise unplayable discs this way.

Sorry, I assumed you were referring to discs you'd just received as was being discussed, which obviously you certainly have something to lose in using any cleaning agent that has the potential to affect the long-term viability of the product. But if all recommended options fail, if it's what works... I'm just relaying the information that comes from the actual makers/developers of these products. There are professional resurfacing companies you can send discs to that charge as little as a couple bucks per discs, depending on how many repair cycles are needed. Usually such is only necessary for light scratches that prevent the proper reflection of the laser, and more suited for dvd repair than bd. And they're always a last resort for a disc that absolutely won't play, but doesn't have deep scratches that reach the membrane. For those there are sprays/liquids you can apply to try to keep out oxygen for a time, but they don't always work. You can even buy your own resurfacing machine for as little as a few hundred, if you don't need to repair too many discs.

I don't know what part of the world you live in, so maybe it's some environmental factor we don't have here, nor any place the discs we've received have been warehoused for any length of time, but of the thousands of discs I've bought/received over the past 35 years, I've never come across such a stubborn white film, as has apparently afflicted so much of your collection. Deterioration of the membrane by way of oxidation doesn't happen overnight. Even if alcohol exploits a weak point in the seal to let air in instantly upon cleaning, the disc will still work for a time. But I certainly wouldn't want to buy a used movie from you.

Obviously it's not as feasible or even possible to watch everything you get in within the return window when you buy a lot. But that doesn't make such any less of a good idea. You certainly should inspect them within the return window for anything obvious. But, it now sounds like you're referring to something that is happening in your home itself, which isn't at all normal from my experience. Are you a smoker? Do you periodically fumigate? If it didn't come that way, there's something in your environment that has to be the cause.

Originally Posted by Vilya

There were some manufacturing errors that caused some early blu-rays to prematurely fail. Several Lionsgate releases from around 2008-2009 and Criterion discs made around 2011 had very high failure rates; the latter due to bronzing.

When a blu-ray is correctly manufactured and reaches us unscathed from crappy packaging and ham-handed shipping, they have proven to be very reliable. I have had extremely few blu-rays fail over the past 15 years and those that did were almost entirely early Lionsgate discs or 2011 Criterion discs.

4K discs have much higher data density than blu-rays making them far more prone to reading errors. A smudge or slight scratch that would not hinder blu-ray playback can stop a 4K disc dead in its tracks. A properly pressed, packaged, handled, and stored 4K disc should enjoy a long life span similar to that of a blu-ray, but just remember that the higher data density of a 4K disc makes it far less forgiving of any imperfections.

That's the rub isn't it? Quality control is at an all time low. The number of brand new UHDs we've received with scratches has been nothing short of appalling. And we don't know exactly how such may affect their longevity. And in that respect comparing to CDs or DVDs or even standard BDs isn't entirely reliable. We can't even trust they're still using a hardcoat. I've had a number of UHDs that scratched with a clean microfiber cloth just like a dvd would. That shouldn't be possible. I assume they figure a hardcoat is less necessary for releases that aren't being circulated through rental outlets these days. And they're probably right. But it still can't be good for product longevity.

Originally Posted by Vilya

I don't perform surgery, so I think that 99.9% medical grade isopropyl alcohol would be overkill, and much more expensive, for cleaning a DVD. The buck a bottle 70% variety more than does the job here.

While lower concentrations are all that is needed for disinfection, higher concentrations (90% and up) have always been what professionals recommend for cleaning electronics, like optics, to reduce residual film or streaking. It's easy to see why such would be desirable for cleaning VCR heads too. If 70% is all you've got, it's still viable. But, it'll leave behind more residue after drying.

[Vilya]

Originally Posted by JurassicBD

I don't know what part of the world you live in, so maybe it's some environmental factor we don't have here, nor any place the discs we've received have been warehoused for any length of time, but of the thousands of discs I've bought/received over the past 35 years, I've never come across such a stubborn white film, as has apparently afflicted so much of your collection. Deterioration of the membrane by way of oxidation doesn't happen overnight. Even if alcohol exploits a weak point in the seal to let air in instantly upon cleaning, the disc will still work for a time. But I certainly wouldn't want to buy a used movie from you.

Are you a smoker? Do you periodically fumigate? If it didn't come that way, there's something in your environment that has to be the cause.

If 70% is all you've got, it's still viable. But, it'll leave behind more residue after drying.

Extremely few of my DVDs have ever had this happen to them. I discuss this occurrence because of how rare it is, not because I have an epidemic on my hands. Among the very, very few DVDs that did develop this problem, the only thing in common that I noticed is that most of them came in white plastic or translucent cases. I have been buying DVDs since the format began circa 1997 and exceedingly few were ever problematic.

The alcohol does not exploit any "weak points" as there likely aren't any to begin with and, secondly, the playback surface is in contact with the alcohol for a few seconds at most and then rinsed off and the DVD is then thoroughly dried. No DVD that I have cleaned in this manner has failed later.

I have tried commercial disc resurfacing and polishing and I have found it to be ineffective. If none of my cleaning methods work, the disc gets replaced. Usually for free, too, but that's another story entirely.

70% alcohol leaves no discernible residue even if allowed to evaporate and dry on its own. The water in rubbing alcohol is distilled water and distilled water leaves nothing behind. It's a moot point, anyway, because I always dry any disc that I clean, whether with soap and water or with alcohol.

My discs have always been stored in their original cases in a climate controlled home. No fumigation has ever been done in my home nor do I smoke and I do not permit anyone to smoke here. I do not even burn incense or light candles. I only allow myself to handle the discs and I NEVER lend my discs to anyone. I even use a microfiber cloth over my hand when pulling a disc from the occasional cardboard sleeve to avoid leaving any fingerprints upon them. My discs are as well kept and handled as they possibly can be.

I don't sell used discs; I keep nearly everything even after upgrading formats. I use the older format as a back-up and sometimes the earlier edition has some unique feature meriting its retention. As I said before, I have been collecting optical disc media for nearly 40 years and my disc failure rate is only about 0.5%. I think that's a pretty damn good track record, which speaks well of both disc longevity and my stewardship of my collection. Even my ancient laserdiscs (and laserdisc player) are in good working order.

[Vilya]

Originally Posted by JurassicBD

That's the rub isn't it? Quality control is at an all time low. The number of brand new UHDs we've received with scratches has been nothing short of appalling. And we don't know exactly how such may affect their longevity. And in that respect comparing to CDs or DVDs or even standard BDs isn't entirely reliable. We can't even trust they're still using a hardcoat. I've had a number of UHDs that scratched with a clean microfiber cloth just like a dvd would. That shouldn't be possible. I assume they figure a hardcoat is less necessary for releases that aren't being circulated through rental outlets these days. And they're probably right. But it still can't be good for product longevity.

All blu-rays, including 4K, continue to have a scratch resistant coating. The key word being "resistant;" they can still be scratched.

If your microfiber cloth is scratching your blu-rays it is probably because there are contaminants on the cloth, such as dirt particles that you did not, or could not, see. I am often surprised at how infrequently, if ever, that people clean their microfiber cloths. They seem to think that they are self-cleaning textiles.

Discs are still being rented. Redbox exists in many retail locations; Netflix still offers their disc by mail service; and small communities in rural areas like mine still have a few video rental stores, presumably because internet service here in the boondocks is so hit and miss. The disc rental market is a fraction of what it once was, sure, but it still exists. Thanks to having other options, you just stopped noticing.

[slimjean]

Originally Posted by Wendell R. Breland

Really don't recall using alcohol on disc but it was the preferred cleaner for tape machine heads, pinch rollers, etc. 99.9% Isopropyl Alcohol was what we used at work. I buy this one for my use.

Using on a metal tape head that evaporates off is one thing but putting an organic solvent on a polypopylene coating makes no sense.

If you care about your media stay away from alcohols on plastic. Wtf!!

[Vilya]

Originally Posted by slimjean

Using on a metal tape head that evaporates off is one thing but putting an organic solvent on a polypopylene coating makes no sense.

I rely upon my experience and by all means you should reply upon yours. I would not have used alcohol to clean the most stubborn of discs across nearly four decades of collecting physical media if it caused any harm. And our discs are made with Polycarbonate plastic, not polypropylene. Polypropylene is what the storage cases are most commonly made with.

I only use alcohol when other cleaning methods fail. When I clean a disc with isopropyl alcohol the playback surface is only exposed to it for a matter of seconds before I rinse and dry the disc. I have saved a few otherwise unplayable DVDs this way. They stayed saved, too.

"The cases are made of polypropylene (PP5) "

https://woollygreen.com/recycle-dvd-cases/

"Almost universally, physical media cases are made from plastic. Specifically, from a compound called polypropylene."

"Great news: CD, DVD and Blu-Ray discs are not made from polypropylene!"

"polycarbonates are used for discs because they are tougher than polypropylene, which is a very desirable feature for a medium for storing literal art. This resilience is, sadly, also partly responsible for polycarbonate’s extremely long decomposition rate. "

https://www.dreadcentral.com/editori...and-heres-how/

Lastly, Polycarbonate plastic has "excellent" compatibility with isopropyl alcohol (rubbing alcohol). See the chart in this article, specifically this line item: "Alcohols: Isopropyl." This detailed chart lists the compatibility of polycarbonate plastic with a wide variety of chemicals.

PolycarbonateAndIsopropylAlcohol.jpg

https://www.calpaclab.com/polycarbon...ibility-chart/

Originally Posted by slimjean

If you care about your media stay away from alcohols on plastic. Wtf!!

You do realize that isopropyl alcohol is sold in plastic bottles, right? Namely High-Density Polyethylene #2. The type of plastic matters and both HDPE 2 and Polycarbonate have excellent compatibility with isopropyl alcohol.

[slimjean]

Originally Posted by Vilya

You do realize that isopropyl alcohol is sold in plastic bottles, right? Namely High-Density Polyethylene #2. The type of plastic matters and both HDPE 2 and Polycarbonate have excellent compatibility with isopropyl alcohol.

First of all you are talking to a chemist. My bad on the polypropylene. It actually didn't sound rate, but my point still stands.

If we are talking even 70% to 95% alcohols, then we are talking about over the counter grade and not scientific grade. So the amount of impurities are a guess at best (and there can be trace presence of methanol). I mean hell in most cases what are we talking a $1 bottle??

As for why they are stored in plastic. CHEAP. Most cases the alcohol is used up quickly and you move on to the next. Does this mean it is fit for playing media? Have you never seen a discolored container? As someone that worked in chemical storage facilities my entire professional life, I can tell you that polycarbonate containers break down the fastest because they are so hard and yes brittle. Regular non dilute isopropyl alcohol destroy it and that is why you store alcohols in glass for any kind of stability in lab work. High Density Polyethylene is typically used (and yes that also breaks down too but of course it is much less prone to drying up unlike the typical cheapo cases), but full proof is what you find in your local bar. Never ever have I heard of polycarbonate being an ideal way to transport alcohol much less use it on a surface that has a wide array of coatings??

The formulations of coating are not exactly regulated. Depending upon the factory, and how cheap the company is, you have seen the results of what poorly UV cured products actually are.

I see your point of using it as an exception, but as others have shown, even the smallest fault can hurt your disc over time.

No way in hell I am using an organic solvent to clean my optical disc. It will cause it to crack and that is just a fact.

The charts you posted are ideal compatibility of pure chemicals. Of course that is a perfect world and from someone that has been in those labs shipping out the chemicals after being formulated, I can say with a certainty bad batches can and do happen. Distilled Water in limited amounts, is all you need and a microfiber cloth.

[Vilya]

Originally Posted by slimjean

First of all you are talking to a chemist. My bad on the polypropylene.

[Show spoiler]It actually didn't sound rate, but my point still stands.

If we are talking even 70% to 95% alcohols, then we are talking about over the counter grade and not scientific grade. So the amount of impurities are a guess at best (and there can be trace presence of methanol). I mean hell in most cases what are we talking a $1 bottle??

As for why they are stored in plastic. CHEAP. Most cases the alcohol is used up quickly and you move on to the next. Does this mean it is fit for playing media? Have you never seen a discolored container? As someone that worked in chemical storage facilities my entire professional life, I can tell you that polycarbonate containers break down the fastest because they are so hard and yes brittle. Regular non dilute isopropyl alcohol destroy it and that is why you store alcohols in glass for any kind of stability in lab work. High Density Polyethylene is typically used (and yes that also breaks down too but of course it is much less prone to drying up unlike the typical cheapo cases), but full proof is what you find in your local bar. Never ever have I heard of polycarbonate being an ideal way to transport alcohol much less use it on a surface that has a wide array of coatings??

The formulations of coating are not exactly regulated. Depending upon the factory, and how cheap the company is, you have seen the results of what poorly UV cured products actually are.

I see your point of using it as an exception, but as others have shown, even the smallest fault can hurt your disc over time.

No way in hell I am using an organic solvent to clean my optical disc. It will cause it to crack and that is just a fact.

[Show spoiler]The charts you posted are ideal compatibility of pure chemicals. Of course that is a perfect world and from someone that has been in those labs shipping out the chemicals after being formulated, I can say with a certainty bad batches can and do happen

. Distilled Water in limited amounts, is all you need and a microfiber cloth.

I'm sorry, but no chemist that I have ever known would mistake polypropylene for polycarbonate. Not for an instant.

I was a Nuclear Biological Chemical Specialist in the U.S. Army, but I claim no particular expertise despite my having worked with lethal military chemicals. Working around chemicals does not make one a chemist. Instead of pretending to have expertise that I do not, I ran my last post by a friend of mine who actually has a doctorate in organic chemistry and my comments were deemed correct, albeit simplified. Polycarbonate and isopropyl alcohol have excellent compatibility in real world applications.

You have not seen polycarbonate used to store isopropyl alcohol because there are other plastics better suited for that purpose; HDPE #2 is the plastic of choice, probably in part because it is cheaper to produce, thus why it is so commonly used. The right plastic for the right job. Retail pharmacies everywhere stock isopropyl alcohol in HDPE #2 plastic bottles, including the 99.9% medical grade variety.

The long and short of it is plain and simple: I would not use isopropyl alcohol as a cleaner if it harmed my discs. Why the hell would I? I have been cleaning discs, as needed, for nearly 40 years. Experience alone has proven that my method is both safe and effective.

If distilled water was all I ever needed to clean a disc, I would never have had reason to try anything else. In fact, plain tap water and a little dish soap is sufficient in most instances, but isopropyl alcohol works where plain water and soap does not.

I will believe the science, my friend with the Ph.D in organic chemistry, and my own decades of experience. You are free to believe anything that you choose.

[slimjean]

Originally Posted by Vilya

I'm sorry, but no chemist that I have ever known would mistake polypropylene for polycarbonate. Not for an instant.

I wasn't mistaking polypropylene for polycarbonate. I made a simple mistake on the makeup of the disc. A big difference. So you don't know a chemist that could make a mistake? So the chemist you know are oh so much better than the ones I know? lol

Polycarbonate as a storage bottle is terrible and they do get brittle. The reason is that solvents are stored in them and ethyl alcohol can and does break it down over time by simply drying it out!

It doesn't take a PhD to understand that or any of my other points. You can believe whatever friend you like. You are given simple advice and no need to be hostile about it.

So let me get something straight, you worked as a Chemical specialist but you are not a degreed chemist but a friend said so it must be true?

What seemed to fly right over your head is that theoretical is not the same as real world applications.

Storing in glass is obviously best, and depending on the impurities and the time it is stored and of course the conditions, are all a factor.

But no chemist in their right mind would store alcohol in polycarbonate containers. The same is true with foolishly washing your discs with alcohol.

Any chemist has worked with "lethal chemicals". So what? We could play tit for tat on that, but I was actually just stating what I have been doing for over 40 years (and my experience is also nuclear formulation as well).

This friend of yours, does he understand the impurities of household isopropanol? Perhaps in his extensive bluray studies he knows the formulation of every coating of every optical disc you have been playing with? In his extensive experience of formulating those coatings is he also an expert on what actually gets sent to the plants for batch operations?

Yeah I have worked with a lot of doctors who like their theories and they are befuddled every time with real world examples that go right past their text book answers. Sad to say, the world isn't perfect and having working with several hundred organic chemists, the ignorance of the obvious have never ceased to amaze me.

I never once stated that you in most cases you can't be fine, but why chance it? What if you have a rare disc with flaws. Why needlessly dry it out an acrylic like coating? It just isn't smart.

The reason I spoke up, is because you are spreading around the nonsense that could hurt other people's discs. This organic doctor you speak about should be ashamed of themselves if they are promoting cleaning media libraries that are often rare. The injection molding materials also vary. It to me is just plain silly to think that one can possibly know the exact formulation of every optical disc.

[Vilya]

Originally Posted by slimjean

So you don't know a chemist that could make a mistake?

With the chemicals that we worked with, chemists that made mistakes were dead.

Originally Posted by slimjean

you worked as a Chemical specialist but you are not a degreed chemist but a friend said so it must be true?

My friend never once said that I was a chemist. Nor did I.

Originally Posted by slimjean

no chemist in their right mind would store alcohol in polycarbonate containers. The same is true with foolishly washing your discs with alcohol.

No chemist in their right mind would mistake a polycarbonate disc with a polypropylene case.

No one but you is talking about storing any liquids in a polycarbonate container. I am talking about taking a few seconds to wipe a disc's playback surface with isopropyl alcohol and then rinsing it with water and thoroughly drying it.

If all other cleaning methods failed to clean an unplayable disc, how is it foolish to try something else? No one would deliberately do anything, yet alone repeatedly, that harmed their discs. What I do WORKS. It is why I still do it.

Originally Posted by slimjean

This friend of yours, does he understand the impurities of household isopropanol?

She probably understands a great many things. She has a doctorate in organic chemistry; what credentials do you have? For someone hereto masquerading as a chemist, you have yet to tell us. Working in a warehouse no more makes you a chemist than my Army service made me one.

Originally Posted by slimjean

I never once stated that you in most cases you can't be fine, but why chance it?

Chance what? I only use alcohol to clean unplayable discs after exhausting all other cleaning methods. I started with a dead disc and I finished with a working disc. Seemed like a smart decision to me.

Originally Posted by slimjean

The reason I spoke up, is because you are spreading around the nonsense that could hurt other people's discs. This organic doctor you speak about should be ashamed of themselves if they are promoting cleaning media libraries that are often rare.

While you are spreading something far more fragrant.

What I am doing is sharing my decades of experience. What I do works. Otherwise, I wouldn't do it. Pretty simple, really.

You really need to work upon your reading comprehension. Most scientists are really good at it.

All she said was that my comments about the reactivity of polycarbonate and isopropyl alcohol were correct. Polycarbondate and isopropyl alcohol have excellent compatibility in real world applications just as I said in my previous post. The last article that I linked to also confirms what she said.

Originally Posted by Vilya

Polycarbonate and isopropyl alcohol have excellent compatibility in real world applications.

[slimjean]

Lets cut through all the personal attacks (which I have not participated in).

Besides putting down my abilities in chemistry work for the last 40+ years a lot of what you are saying is skipping over the finer points that I made. It is like you have thrown such a fit that you didn't even look at the meat of what I was stating.

Consumer grade alcohol is unreliable, optical discs are not manufactured the same. The coatings are not even regulated. No doctorate in chemistry can possibly know the real world examples of what can happen with a flawed disc.

So in closing, I misunderstood. You go from the "extremely rare" and the 0.5% to now the "40 years experience" using 70% rubbing alcohol.

What exactly is this great scientific study again? There have been several posters that tell you the dangers of using a 70% alcohol that has impurities that the industry does not have to report. Again METHANOL is often in trace amounts, and that is why they are not used in research conditions.

Before you go jumping all over people's careers and state your "40 years" of research experience, lets call it like it is. You make exceptional cases of washing off plastic disc with an organic solvent and got lucky.

You choose not to take advice and crap all over people such as myself because they don't share your view.

Forget any kind of chemical answer, even the basics of industry being sloppy with regulation should be enough to tell you that the flaw in your well taken care of disc may not have even been your fault. Yet you are saying with a certainty how impossible it is that the consumer grade chemical can have an impact on what could be a flawed replicated disc to begin with?

[Vilya]

Originally Posted by slimjean

Besides putting down my abilities in chemistry work for the last 40+ years a lot of what you are saying is skipping over the finer points that I made.

Like skipping over my simple question: what are your credentials, exactly? I should not have to keep asking.

Originally Posted by slimjean

You go from the "extremely rare" and the 0.5% to now the "40 years experience" using 70% rubbing alcohol.

I have experienced about 0.5% disc failure to date meaning that these are discs that could not be made to work.

I have used 70% and 91% isopropyl alcohol for far longer than 40 years and for many different things. Notice how that says NOTHING about the frequency of that usage. It is all part of reading with comprehension. I use isopropyl alcohol to clean discs only when other cleaning methods fail and that is indeed an extremely rare occurrence, but it has happened at different times over the last four decades.

Originally Posted by slimjean

What exactly is this great scientific study again?

I made no mention of any "scientific study."

Those words do not appear in any of my comments until now. I provided you with three links that are easy to understand, no chemistry degree required. I would suggest that you read them again, but you only seem to see what you want to see.

Originally Posted by slimjean

Before you go jumping all over people's careers and state your "40 years" of research experience, lets call it like it is. You make exceptional cases of washing off plastic disc with an organic solvent and got lucky.

I ask for the credentials of anyone claiming expertise. That is not "jumping" on anyone, but a simple and reasonable request. I already told you what I was and wasn't; why can't you do the same?

Good luck has nothing to do with it; science does, experience does. My method has worked for decades. Luck does not last for decades.

Originally Posted by slimjean

You choose not to take advice and crap all over people such as myself because they don't share your view.

Yet you are saying with a certainty how impossible it is that the consumer grade chemical can have an impact on what could be a flawed replicated disc to begin with?

Cleaning a disc with anything will not correct a fundamentally flawed manufacturing error, but it may remove residues that prevent a disc from being read.

Asking for your credentials is not an insult nor is it an invasion of your privacy. It is a reasonable question asked of anyone calling themselves a "chemist."

Originally Posted by slimjean

First of all you are talking to a chemist. My bad on the polypropylene.

I have never once met a scientist that would not reveal their credentials when asked. They answer the first time, too.

Do what you want with your stuff and I'll do the same. I'm gonna try some of that "luck" of mine on a lottery ticket.