Tonight I found out that soaking rusty nuts and bolts in a mixture of white vinegar and lemon juice will remove pretty much all rust, paint, coating etc. I have a bunch of big bolts and nuts from steering stuff on my firebird and didn't want to replace them. But several were very rusty and needed a lot of PB to come off. I hit them quickly with a wire brush and let them soak over night. After another scrubbing, they were down to bare metal. I didn't take a before photo but here is what they looked like before paint. It was super cheap and worked great. Hopefully this will help someone else.
http://i378.photobucket.com/albums/oo225/ceharrisnanny/bolts_zpsdd570320.jpg