#0000 steel wool or rubbing compound to clean them.
If they are pitted you won't fix them unless you send them to be replated.
You can touch up any black areas by cleaning, careful masking and spraying with low gloss black such as SEM Trim Black aeresol.
I agree with TechNova - takes a lot of elbow grease.A friend recommended Flitz Buff Ball witch you can get at any parts store or Walmart.Goes on a power drill.Saw an add for it on the weekend auto shows. I'm planning on using this on my trim. Anyone tried it?
I ended up using super fine steel wool and I dipped it in some acitone to help take the paint off and it worked but i think it might have taken some of my finish off to but it looks way better than it dit so Im happy.