just thought of another i'd heard...
i remember a guy i used to work with was also really into burning music. he would simply use car polish. not the paste-y type, but the high shine clear ones.
all you're trying to do is fill in the scratch (or remove it by abrasion). usually the data is not hurt, just the surface. and the laser can't deal with the refraction issues caused by the (now) uneven surface.
here is a link for a company that 'fixes' cds and dvds, if you choose to go that way. $3.00 per + $3.00 postage.
http://www.ryatec.com/information.html