I've have one of those hand turned scratch repair do-dads and it works, but as mentioned, it does leave the disc looking cloudy.  I'm a little "superstitious", so any favorite disc so repaired would probably get replaced eventually.  I have some concerns about the long term viability of a repaired disc.  The sound doesn't seem to be affected, but I worry that the abrasive action on the whole disc surface could cause it to fail prematurely.  Of course, only time will tell.