After 15 years of use, one of my Alps mechanical selector switches (metal contact spring dragging across metal tracks) had developed oxidised/dirty contacts.

After some cleaning with alcohol and Kontakt 60 the contacts are once more shiny and the switch is ready to be reassembled. - Just one last issue: should the contact spring which drags across the contact tracks be lubricated or protected against moisture?

If yes, using what? Silicone oil/grease, WD 40, watchmaker's oil? Or is keeping everything dry and clean best?