We pop out the
eye ball with a quick twist.
Cult of Mac adds: Ah, we remember the lost art of cleaning mechanical mice...
Opened up, we find plenty of plastic viscera, two quadrature encoders and a few resistors. Surprisingly, that's about all we find.
This simplified design decreased costs and improved reliability by moving the complex circuitry out of the mouse and into the desktop, paving the way for cheap desktop mice for years to come.