How do I clean a CD and what types of discs cannot be used with this unit?

To clean a CD, wipe the disc with a soft cloth in an outward direction from the center. The following disc types cannot be used: DualDiscs, 8-cm discs, oddly shaped discs, discs other than CDs, damaged discs (cracked, chipped, or warped), and CD-R/RW discs that have not been finalized. Do not write on or apply chemicals to the surface of discs. (Page 44-45)