I have a Mitsumi serial ball mouse that I am very fond of (it has been with me for the longest time). I periodically remove the ball, clean the inside and the bearings with alcohol and a cotton tip, and wash the mouse with soap in the sink.

Lately, it has been acting up. It works fine when moving above a certain speed or across more than a certain distance but when trying to make fine tune movements, particularly on the vertical axis, it does not register even though the ball is rolling. It works fine if I remove the ball and manually and slowly rotate the bearing for the vertical movement, so I am thinking for some reason there is no more friction between the ball and the mechanism..

This may be just old age, and I may have to deal with it; but is there a way to fix this and was there a way to avoid this? How do you care for your ball mice?