IBM Model F keyboards
Once upon three and a half decades ago I was installing and repairing personal computers.
Servicing IBM Model F[?] keyboards we'd usually just remove the keycaps, give them a soapy bath and reattach them the next day.
Occasionally a keyboard would be in such a state we'd disassemble it past unscrewing the plastics and by straightening the metal tabs within further disassemble it. We'd then hose it down with a Freon product and reassemble it.
They'd reassemble, look and work a treat but we probably didn't do the ozone layer any favours.