Originally Posted by
JohnDThompson
Take the arms off the bike, disassemble all the bolts, brush off the loose rust with a wire brush and then drop them in a bowl of dilute oxalic acid to get rid of the rest of the rust. .
Alternative (and I do it all the time with rusty parts; and you don't have to deal with harsh chemicals that might be hard to find) : Take them off, pop them in a clean glass pasta sauce jar (or whatever glass container), add el cheapo white vinegar (available at most grocery stores) to cover the parts (at least). Let it sit for a week. Take them out, scrub, dry very well. All done... Note: Do not cap the jar.