Re:
If polishing and tinfoil don't do it, a bath in Oxalic acid will lift the stubborn rust without damaging the plating. It's used as a wood bleach, so available from home centers, also used for cleaning stubborn stains on boat hulls, so if you've a nearby marine chandler that's another option, I grabbed a 5lb sack off ebay after tripping over some youtube videos.
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