Mono Twin Amp Stereo Switch Exhibits Charring

[rkic]

The contacts on switch S2 appears to have some black charred spots on the contacts. I noticed this when I was replacing the .1uf input caps (C1 and C12).
I haven't hosed down any of the switches, contacts with Deoxit yet. I'm leaving that for the last step - don't ask me why.

Is this normal with an amp this age?

 

[Dan ʕ•ᴥ•ʔ]

Are you sure it isn't oxidation? Some contacts are silver-plated and will tarnish to black after a period of time.