I've got a method I've been using with great results. Thought I'd share.
- I clean the old part with any degreaser, really clean, and when dry, spray lightly with LPS electro contact cleaner to remove traces of solvent and other residue. The idea here is to have a uniformly clean surface to apply the next step.
- Wet the part with water (very important to avoid streaking). Then with great care (wearing rubber gloves, long sleeves, dust mask and eye protection) apply the phosphoric acid with a nylon paint brush. I brush it around over the whole part for about two or three minutes in a sink, rinse and repeat. Do not splash the rinse water or straight acid on your body---very harmful and toxic---. Rinse thoroughly again, air dry or use compressor. The part should now be very soft white in color. If it is blotchy, you probably didn't do a good job with step one.
- Now the fun part. This Flitz shit is amazing. Don't know what's in it. Some secret German formula. Apply with terry cloth just llike your mom's silver polish. An incredible amount of black oxidation will come off in the cloth. I did my carbs inside and out including the slides. After satisfied that you've got the worst of it, polish lightly with a clean bit of cloth and your done. It works wonders without a huge effort!
Before and After:
BTW, at datchew's request I made this thread a sticky. Need more material. I'm sure there a million more ideas out there.