The following was lifted from a Customer Reviews Of Microsoft TrackBall Optical Black Mouse. I've tried it and it works.
PROBLEM: You've just cleaned the ball and bearings, and now it feels weirdly reluctant to move with your thumb, as though it's developed a sticky coat & is clinging to the cage walls.
SOLUTION: The ball likes to be cleaned with plain water and dried with a cloth or soft, absorbant paper towel. When you pop it back in its cage, place your open palm flat against it and roll it FAST up, down and around for a few fun moments. You should feel the drag disappear (don't ask me what's going on in there!). I like to end with a final palm-flick, and listen to the ball fly in there for 2-3 seconds. Sweet!
PROBLEM: The ball has become sluggish without being cleaned.
SOLUTION: Yeah, clean it and the bearings in the cage. You can do it wet or dry, just be sure to spin it afterwards for maximum joy.
