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

Rcprince has the right idea. I have used turtle wax to fix some cds. put small amount on scratch, let it dry, then very gently wipe off with TP. I've also seen a couple of cd "fixing" machines used in cd stores, so if you claim your cd is scratched, they'll fix it before returning your money. one was a sort of buffer using buffing compound, the other machine encloses the cd and it uses water and wax compound. good luck.

Novus #2, available at an plastics store.

EAC works...resurrected my fave Dave Lindly CD which had horrible digital skipping on two tracks; the clone is better than the original. EAC is tops; it is used by live taper types for mastering their recordings, too.

What is eac?

EAC is Exact Audio Copy. A software program for copying discs. It is freeware as far as I know. It works great, too.
You might also try Auric Illuminator. I've had good luck with it. Polish the disc and it may play perfectly, or at least better.