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.
We had to flip the mouses around at the end of every computer class so the teacher could check all the mouse balls were still there.
Yup. I was a nerd who got to go inside and boot up the computers and set them back from what the kids had done the day before every morning. Warning sounds with SNL skits were popular at one point, as was messing with the icons.
It was instead of standing outside in the cold wet concrete courtyard for 20 minutes before the first bell.
First job was turning the mouses back over (the were left balls up at the end of each class).
Out go to prank was a shut down bat file, disguised as GTA.exe. We used to put that in a shared folder and waited for other students to shut down their computers.
Ha, these were early Macs (right at the launch of System 7) there was only a few kids with these at home so I had a pretty good idea who was brining in the icons and sound files (aiff if I recall correctly). We had one at my home too btw. They were interesting computers but besides shareware and a couple game companies, they were abysmal for games. We did get a copy of Warcraft 1 and could play it over 14.4k directly dialed to the other computer lines with PC users.