We don't want to remove silver tarnish, because
it is perfectly conductive!
If we polish thin silver plate, we're removing beautiful conductor,
thinning the plate, allowing the base metal beneath to, itself, tarnish (which is basically irremedial!)
Don't polish black silver contacts. Just don't do that, please!
Milspec stuff from before WWII is all silver contacted, and still working without a need for a "polish". It's nickle plate, tin plate, zinc or any other metal, that causes contact resistance. But not silver! Silver is better than gold.
that's my hector-lecture for today, lol!
never polish silver plate unless it's granny's pisspot