Morehpperliter recently had issues with his Blackberry’s track ball no longer registering clicks after he spilled coffee on it.  I have revived a Blackberry or two with a rubbing alcohol bath, which is what I suggested he do.

I suggested that he pull apart the Blackberry and bathe the track ball assembly in alcohol, along with cleaning the track ball contacts on the system board with an alcohol-soaked Q-tip.  After he did this, it was good as new!

This will work on devices having issues registering movements of the track ball as well.  You might even be able to simply drip some alcohol on the track ball of a Blackberry with the battery removed to de-gunk it.  I have not tried that method of cleaning it up, but you could give it a shot if you are shy about disassembling the entire handset.