Cleaning the Trackball and Rollers
With the phone off, you should be able to see the LED and clean it with a cotton swab and alcohol. Once this is done, the trackball should no longer stick.
Clean the small rollers on the trackball. If you want to clean the trackball itself, you can, but you must be careful when disassembling these parts. Take the metal ring off the top of the trackball. Two different halves should separate so you can get to the trackball. If the small rollers pop off of the trackball, they will go back on, don't worry.
Try using a little bit of denatured alcohol if you want to clean the actual trackball, simply place the ball in the solution and shake it back and forth for a few seconds (this process doesn't require more than a few shakes). Then clean the ball off using a simple cup of water or by simply running it under a faucet.
For more tips on how to clean your trackball, check out: BlackBerry Troubleshooting Tips.
Once the trackball has been cleaned with the alcohol, and then water solutions, dry it off with a light cloth. Place the rollers back on the trackball, then reattach the metal ring. Place it back into the LED and put the ring back on.
Your trackball is clean! This process can be done as needed to keep the trackball moving smoothly.