Ed note that should have been mentioned. NEVER wash CDs or DVDs like "plates" in a circular motion. Always grab it by the edges and start with a lint free cloth (ones that are made for cleaning glasses or TVs are great..3M has a good one) and wipe it a radial manner. NEVER circles. It is really easy to screw up the data that way. Especially on a virgin disc that is new.
If THAT doesn't work, use soap and warm water or rubbing alcohol. if THAT doesn't work (deep scratches) get a product called "Disc Dr." It grinds off a fine layer of the coating of a disc. Works like a CHARM, even on the worst I have ever seen....my brothers!