Bring them to a used music or game store and have them resurfaced on a professional resurfacing machine, not a disc doctor. Someone on CAG once traded me a game that was in abyssmal condition (after telling me it only had minor scratches), deep gouges, would not play, would not read, wouldn't do anything. $3 later, its in mint condition. They might charge anywhere from $2-$5 for each disc, depending on where you live.
The mom and pop or regional places have them more often than the big chains... EB and Gamestop usually don't have them.