i take terrible care of my dvds and cds and they are all scratched. has anybody ever used those dvd/cd scratch fixers they sell at best buy, etc.? i believe you insert the disc and the machine polishes off a thin layer of the plastic in an attempt to remove the scratches. i was thinking about buying one but would like to hear if anybody knows how well they actually work. or if they are just a piece of junk. thanks.