Vintage Speakers Help

[ijokr]

I recently found for speakers that my dad own and claimed them since they're were sitting doing nothing. Two are the Pioneer hpm 100 (I've read great things abouth them, I believe they're from 1979 approx.) and the other two are the Pioneer Cs-e 9000. The finish and the grille are seriously damaged but not enough to damage the speakers. I might check Craz-Blu's finish project wih the Polks. Any help of how can I repair them or know if the speaker (audio wise) is damaged? Obviously other than hearing hissing or distortion, but maybe they're not sounding the best they can and I wouldn't know since they're too old. Any help would be appreciated