i thought about repairing a cd once that was still readible. i remember the kit that i saw specifically said it repairs unreadible cd's. but a boomer here told me that those repair kits don't always work, so i gave up on the idea.
if i remember correctly, toothpaste smoothes out rough edges on plastic. my dad once buffed up the scratched head of a flashlight once with it, but i'm not quite sure if it'll do the trick on a cd.
Guybrush: I'm on a whole new adventure.
Pirate: Growing a mustache?
Guybrush: No, Bigger than that.
Pirate: A beard?