QUOTE
Top is usually fatal
Bottom. You can get machines. Might work.
Depends on what you call "top" and "bottom". The side that needs to be clean and scratch free is the side
without the label or where you might write on it. It's usually on the bottom when placed in any CD/DVD player/reader I've ever seen, that's usually why it ends up with so many finger prints; the top side gets a thumb but the bottom gets three or four fingers! Of course, one
should always pick these disks up by the edges — except when they fall into the peanut butter and jelly sandwich before the two slices of bread are mated...
Since you already have a new disk, why not experiment with the 'damaged' one. These things are basically coated with lacquer, so you'll need to be careful what you use for a solvent. Likewise, the cloth should have fibers as soft as a babies bottom after a good soak in a warm tub! Apparently wiping from the center out or vice versa is the standard advice for wiping. Seems counter-intuitive but who am I to argue?
Good luck! If you're successful, you might have a new job on some S.F. street corner!