Scuff/scratch removal techniques?
Recently, a three-disc box set I'd purchased on Discogs turned up with an undeclared surface scuff near the outside of a disc (on the data side, not the label side). The scuff affected play: when I tried it out, the player couldn't transition cleanly from the second-to-last track into the last track. Sometimes it skipped repeatedly and then landed way ahead of the problem location; other times it just gave up and skipped to the end of the disc and stopped. I contacted the seller, and they more than did me right: they refunded me the cost of the set without requiring me to send it back.
I didn't want to try "fixing" the scuff when I thought it likely I'd be returning it, because if I failed to fix it or made things worse, I didn't want it suggested that the problem was my doing. But now that I'm not returning it, I'd like to try to remove the scuff if possible: the disc is already messed up, and I'd already be seeking out another copy, so I figure I might as well try. If I succeed. I'll probably end up trying to send some money back to the vendor, since I did get something out of it.
But I've never done this before, so I don't know how to go about it. I've heard of polishing out scuffs, but not how it's done. There are sources on the web; but they say conflicting things.
Have you ever done this? How did you do it?