Used ALPS Power Switch for Sansui AU517 amplifier, but it could be used for other model AU series vintage amplifiers (for example AU717).
As you can see, I disassembled the switch and cleaned it but not by contact liquids, because it is mains power switch... I cleaned it with a dry method (with a brass brush) so now contacts are like a new!

It is getting harder and harder to find these switches today, especially cleaned on this way!