How do you fix an ''out of print'' scratched CD ?

You might try ripping it with something like EAC and reburning a new copy. EAC will keep trying to read the sectors until it gets an exact copy... Can takes hours and hours, but it might give you a "true" copy...

You could also try eBay...

I believe that there are some products out there which are designed for this sort of thing, but at more a last resort--you might check Music Direct or Elusive Disc to see if they have anything like this. The one I saw advertised years ago (Buff Stuff?--I think it was actually tried in Stereophile) was almost like a car wax, a little abrasive to smooth the scratch then buffed to a clear shine. Anyone out there tried car wax for this application?

Go to best buy or similar and buy a disc cleaning/scratch removing kit. They help.
Otherwise, very fine polishing compounds like jewelers rouge (I thinks that's how to spell rouge?). Very fine polishing compound for cars will work great too. Keep in mind to rub from the center hole to the edge only-no circular motion and don't clean like you would a record by spinning it.