This article explains when and how you should clean a mechanical mouse. It does not apply to the the Apple Pro Mouse.

You should clean a mouse if it is does not track smoothly, or if it jumps or skips. A mouse contains a small ball that must roll smoothly for the mouse to work properly. You should keep this ball free of dirt and oil by using the mouse on a clean, lint-free surface, and cleaning it occasionally.

Use the following procedure to clean a mouse:

1. Turn off your computer.
2. Turn the mouse upside down and rotate the plastic ring on the bottom counterclockwise to release it.
3. Turn the mouse right side up with one hand and catch the ring and ball with your other hand.
4. Clean the three small rollers inside the mouse with a cotton swab moistened with water. Rotate the rollers to clean all around them. If there is a build-up of material on the rollers that the cotton swab does not remove, you can use your fingernail to gently remove the material.
5. Wash the mouse ball in soapy, warm water with a mild soap such as a dishwashing liquid if oil from your hands has collected on it. Be sure to dry the mouse ball thoroughly.
6. Gently blow into the mouse case to remove any accumulated dust.
7. Put the mouse ball back in the mouse case and replace the retaining ring.