I just had an adjustable rocker arm that I bought off ebay cleaned up.
I thought it could be hot-tanked, but fortunately the guy I took it to said the pedestals were aluminum and would be destroyed. This thing was caked in thick sludge. He took the arms off and put them in a solvent tumbler with little metal barrel shaped thingies (not sure of the technical name), and polished up the shaft a bit.
Good as new, or close enough for jazz anyway. Didn't take the adjusters out to clean the threads, and was wondering if I should, or just leave them as is? The thought here is that maybe cleaning them would free them up too much? I have a tap and die set and could chase the threads but perhaps that's not a good idea?