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In this case I would unpin the scales simply because there is so much active rust to deal with and it appears to occur under the scales at the pivot. Tough to tell from pics though, so if it is clear...

And here's the place to start for anything to do with repair/restore - check out the first section in particular:
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I say go for it. It really doesn't take any special equipment to deal with rust: sandpaper, steel wool, micromesh are all good. Throw in some metal polish, and you're pretty well set. It just takes...

It looks to me like there's quite a bit of work to be done there. Main points that I noticed are the active rust (especially on the edge) and the hone wear. I'm sure it could be cleaned up and...