Is there a way to know your code is still active without actually redeeming it?

[rexcrk]

I wasn't sure where to post this, but I decided to here since I have a few extra codes I've been thinking of selling.

There are two concerns I have with this;
1: Sometimes I'll have multiple codes of the same movie (like, if a new edition of said movie came out) but I don't remember which one I actually redeemed >_>
2: Sometimes it'll say the code has an expiration date, but will still end up being able to be redeemed (which is awesome).

I'd love to make a little extra cash, but I'd really hate to sell an expired or already redeemed code by mistake.