No, we don't put mice through the dishwasher, although we may try that someday. Optical mice are sealed units, and so require little more than an occasional wipe with a damp cloth. How often you need to clean a mechanical mouse depends on your working environment. When we still used mechanical mice, Barbara, who is a true neatnik, needed to clean her mechanical mice only every few months. Robert, who smokes a pipe, needed to clean his mechanical mice every few days.
The best sign that a mechanical mouse needs to be cleaned is when mouse movement suddenly becomes jerky or intermittent, particularly if the problem is limited to one direction. A mouse has two cylindrical rollers, one each to capture horizontal and vertical movement, and may also have one or more idler wheels designed to keep the ball in position. Dirt on these rollers and wheels is normally the cause of jerkiness and other movement problems. The best way we've found to clean a mouse requires only a soft cloth, an old toothbrush, and a bottle of rubbing alcohol. Take the following steps:
Dampen the cloth with alcohol and use it to wipe down the mouse cord and the exterior of the mouse.
Remove the plate that retains the ball and allow the ball to drop into your hand. Use the damp cloth to clean the ball and plate thoroughly and set them aside.
With the mouse upside down and using a strong light, look down into the hole normally occupied by the ball. Blow or shake out any large fluff balls or other accumulated trash.
Dip the toothbrush in alcohol and use it to scrub the rollers and wheels thoroughly, making sure to get them clean from end to end and all around their circumference. Because of the rolling action, hair and fibers can become knitted in a mat around the rollers, to the point where they're almost welded to the roller. If the toothbrush won't remove the mat, use the edge of a sharp knife gently to break up the mat without scratching the roller and then use the toothbrush to remove the freed junk.
If the mouse has a wheel, the bottom of the wheel is probably accessible from within the mouse housing. Use your finger to press the dampened cloth against the bottom of the wheel while you rotate the wheel from the top to remove accumulated grunge.
While you're at it, use the damp cloth to clean the mouse pad and the desk immediately surrounding it.
But before you spend much time cleaning an old mechanical mouse, consider replacing it with a modern optical mouse. Good red-eye mice are available for less than $20. They're durable, provide more precise pointing than a mechanical mouse, and need only an occasional wipe with a damp cloth.