Don't we use tinning to lightly or promptly ... they'd have to be really corroded before i'd re-tin them~~~~~ but as available they may be.,if those grumbled up ones have good service history, why trashem?
you want to preserve the brass/copper finish as close to specification., coating them up with anything less conductive than the contacts material may grow over their surface.......and produce a loose or restrict electrical conn
nothing ! I'd just resurface them with mild metal grade sandpaper, use any tools material handling compond on them, even brasso=AE, it leaves them sharp on point and shiney to the eye.
OR/AND until i could get new ones };-)
=AEoy
Another Empty Mansion ?
Best Wishes, Attentively };-) Roy Q. T.
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