Guess I could try the stem of a paper match, that might be small enough. I'll try the silver cleaner first and might try gluing fine sandpaper strips to the match stem for polishing. Thanks for the silver cleaner tip.

The tiny points are recessed in plastic so not much clearance for good access.

I spent a lot of time learning soldering in my early days with IBM but the components were much larger 60 years ago. We could pull most of the logic relay contacts out and polish them with a pencil eraser.