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.
Jesus, I was using Turbo Pascal in the 80s. Had no idea it even still existed in 2000. Flex: I wrote my own BBS in Turbo Pascal and ran if for a couple years in Portland - Tomb of the Unknown Modem.
It was still version 1.0 from 1987 or so