Turn on your faucet and run warm water over the underside of the CD. Gently rub your thumb over the CD as you continue to run warm water over it.
Pour 1 drop of liquid dish soap onto any greasy streaks, and rub it in with your thumb while continuing to pour warm water onto the CD.
Shake the CD to remove as much water as possible, and then lay the CD on a towel, with the underside facing up. Let it air-dry.
Rub a small amount of white, non-gel toothpaste onto any scratches on the CD with a microfiber cloth. Rub from the center of the disc to the outer edge of the disc, but do not rub the cloth in a circular motion.
Rinse the toothpaste off the disc with warm water, and let it air-dry.