This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
The best mouse pads are cloth-covered 1/8" - 1/4" rubber foam. The cloth should have a slightly prickly feel when brushed by your finger tips. Such pads offer some resistance to mouse movement. This makes positioning easier and helps reduce fatigue. The worst mouse pads are plastic or plastic coated. These usually offer little resistance to movement and transfer hand oils, dust, and other gunk into the mouse so rapidly that cleaning becomes a nearly daily chore. Cloth-covered pads do get dirty. It's a good idea to wash your mouse pad every couple of months. (Use warm soapy water, rinse, blot with towel, and let dry.) -----------------------------