Dunno what made me think of this just now. When I worked for IT in a school district way back in the 90s, a librarian told me she kept a supply of mouse balls in her desk because kids would steal them out of the school computers. What I remember about those balls was they picked up dust and crud off surfaces. Pretty soon optical mice came along and they were history.
Nope. Way back in the day turning the brightness on a monitor completely down was the big prank. I do remember cleaning my mices balls and I did not relish that. When optical mouse came down in price I bought one for every family member.