Apple’s Mighty Mouse is a good mouse in my opinion. Some people really like it, some people don’t. One of the main complaints I have heard is that the top scroll ball becomes inoperable over time due to the collection of gunk. Dirt and grime from our fingers can collect on the little ball causing the sensors to stop functioning.
Cleaning the scroll ball is really a snap. Simply lay a sheet of plain white typing paper on a sturdy, smooth flat surface. Turn the mouse upside down and with light pressure, move your mouse in a circular motion with the ball against the paper for about a minute. Don’t press too hard – you don’t want to damage your mouse. You’ll start to see little lines of gunk appear on the paper as the scroll ball is cleaned.
After a cleaning, your Mighty Mouse should be mighty once again!