David,
I smoke, drink coffee, and spill beer on and around my mouse pad a lot,
so naturally I clean it very often.
1) Remove the cover on the bottom of you mouse
2) Moisten a Q-Tip w/ rubbing alcohol
3) scrub all the little rollers with the q-tip
4) if you want to scrub the ball too, or you can soak it for a minute in
alcohol.
I've done it plugged in before, but you may to unplug it just in case
Casey Marion