De-rusting some stuff

Yes sir. 12 volt. I ran 40 amps but they say 10 is fine too. Just the little 2 ampers would take forever.
I can't remember what mine is I think its 2 -6 amp or 2-12 it had a selector on it you can chose like 4 different amps. That is very cool iv never seen this done. So the hot side goes to the 4 pieces of reber and the ground goes to the part?
Does it remove old paint and grease too or just rust?