couple quick cleaning questions?

Just 3 issues/questions if anyone can lend an ear and a hand?
Alot of my hardware( just hex bolts, namely) are accumulating rust and are starting to get a lil' orange...should I swap out, or is this a trick to putting them in SOME kind of cleaning fluid to get 'em nice and clean again? If I need to buy new, where's the best place to get? dealership or online somewhere?
I've got alot of chrome, but also ALOT of aluminum- what's the best way to clean up the aluminum? No rust, and not really dirty, just looks like it just has some aged buildup of somekind on it all....sorry, I barely know what I'm talking about!
Lastly, on my air filter cover(is there another name for it?) The outside of the chrome cover is in good shape, but the circle disc in the middle is nasty(Where it says "fat boy, 80 cubic inch" etc, etc....Do I need to replace the whole cover or just the middle disc?
Thank you all SO much for your patience with a HD n00bie.

Just popped off my a/c cover and the filter is FILTHY...I'm 2 seconds from buying a recharge kit...will the kit actually remove the dirt from the filter, or would I be better off buying a new filter?
Sorry for the very elementary questions...I'm learning! I appreciate everyone's patience and help thus far!




