I have been unhappy with my track ball for about 10 months because it sticks and does not roll smoothly. Today I figured out a solution: I applied "carnauba" car wax to the three support balls and to the main ball. Now my trackball glides smoothly and effortessly. Any brand of car wax should do it.
I really like the track ball because it does not get near the end of my line and "bump" into something on my desk like a conventional mouse does.
Cheers! Bernie "Happy track ball guy"