Tip: Trackball mouse getting a bit sticky? Rub your nose or forehead with the finger or thumb you use to control it and presto! That trackball will be rolling like new.
I have a MS Trackball Explorer that is controlled with the index finger. Sometimes it gets sticky, I think due to hand perspiration or dryness. In any case, after thinking about where I could find some lubricant that would get that ball rolling smoothly again but having no actual oil around, I realized faces are full of it. Sure enough, it worked! So, if you have a stickyness problem with your trackball, try this and it will blow your mind.