I might be wrong about this, but I think that the electrolysis method actually converts the rust back to base metal, while acid methods remove it leaving depressions where the rust was. Also, I think that acid does remove clean metal from the entire object, only at a slower rate, depending on the metal and the acid. That's how etchings are made.
While neither of the above (if true) is important in just cleaning up many tools or metal stock, it might be more important for something like gage blocks. If untrue, then please ignore.....
I have thought about how, using electrolysis small objects like bolts etc might be more efficiently de-rusted. If they are laid on a plate which serves as the anode, immersed in solution, I think it might work.
I have also already tried a towel wetted in washing soda solution with a cathode plate over to remove surface rust from the top of my mill table and it worked well. Perhaps the reverse might also work -- a cathode plate, a towel -- or several layers of towel, the gage blocks, and then another plate for an anode. If the blocks are relatively similar in thickness the towel might make up for the height difference.
