for those who wish to keep their balls clean....
the best way is to use rubbing alcohol on the ball(sounds painful?)
the get a Q-tip and dip it in the alcohol the run it inside and all over the nuts and wheels, scrub the ball with a sponge, and clean themouse pas once in a while
alcohol works great but you still need to clean or replace your pad every 2 months due to dirt build up
or do like me and Mouse did go optical