For commercially-pressed CDs and DVDs, 70% isopropyl alcohol is best.
For consumer-burned CDs and DVDs, plain water is best.
In both cases, use soft cotton or other non-scratching cloth material.
For getting rid of dust or lint, use tall-size canned air. Do not use the compact air cans, as they tend to spray liquid. Also, always make sure to keep the can upright, do not tilt more than a little.
For example, I'm currently using 3M 10oz Dust Remover canned air. I intentionally avoid the OfficeMax brand canned air, as their tiny cans spray liquid and cause damage. Not all canned air is created equal.