| Field | Computer hardware |
| Went Obsolete | Round the turn of the century (depending on country) |
| Made Obsolete By | Optical (IR/Laser/Other) mouse |
| Knowledge Assumed | None |
| When useful | If you happen to break your modern mouse and find an old one in the attic |
Turn mouse upside down. Find the ring that holds the ball and twist it counter-clockwise. Turn the mouse back right side up and the ring and ball should fall out. Next clean the ball (don't scratch it!), and clean the rollers inside the mouse from lint, hair or other nasty substances. Replace the ball and ring and twist the ring into place.
Some public and multi-user terminals still use ball mice as a cheaper–and less likely stolen–alternative to optical mice. These are sometimes glued shut to prevent the ball from being removed.
Though the knowledge of how to clean the ball inside of computer mouse may be becoming more obscure, the skill is still applicable in special circumstances, such as Apple's Mighty Mouse (http://www.apple.com/mightymouse/) and trackball mice.