Tips for cleaning very tarnished contacts on an old Alps rotary slide switch.

[delverboy]

I've managed to get this old Alps rotary slide switch apart and am wondering what the best solution to cleaning the contacts would be. Looking at how tarnished they are I'm guessing they are silver or a silver alloy?
I tried contact cleaner, which helped, but I was still seeing an inconsistent .3 to .7 ohms across the contacts which is why I took it apart.

 

[rayma]

Try deOxit D5, but there is also mechanical wear.

 

[Andersonix]

If you can see what you're doing try crimping those sliding contacts to make more spring force? But some of those fixed contacts look worn. Try dielectric grease for better contact?