I was watching an episode of Physics Anonymous a couple of days ago, the episode where they were tearing down the chuck on the lathe they are rebuilding. They tried several methods of rust removal, mechanical abrasion, Evaporust, electrolysis, and something else - I believe it was drain cleaner? They then compared the results, both the electrolysis and the Evaporust got rid of all the rust, but the Evaporust seemed to leave all the surfaces with an etched appearance. While the electrolysis left the polished machined surfaces smooth and shiny. The drain cleaner didn't do anything, and as expected the mechanical abrasion left scratch marks on the surfaces.
Maybe they left the parts in the Evaporust too long, or it might just be another reason to give electrolysis a shot.
Don