I use this method to restore old tools and parts. Even cleaned the rust out of my 1972 Honda motorcycle tank. Works like a charm. My wife asked me to help her with a chemistry project so we made the video on an old pipe vise I had laying around.

Steel from anything. Maybe not stainless steel. Just remember whatever you sue as the cathode (what is drawing the rust away) is going t be pretty much ruined for any other use. Also it is directional as in line of site from the part to the cathode. This means if you have something with rust on two sides after some time you must turn your rusty part around to the back side will get cleaned as well. Its the absolute best method I've used and its a lot cheaper than evaporust.

If you do want to try the electrolysis method for bigger items, and I mean BIGGER, do what I did. Get a cheap kiddy pool make the mixture and let it go to town. I had a rusty old lawn mower deck I saved with this method. I just moved the cathode to different sides and in a couple of days no rust. Just washed it off, primered and painted.
Evaporust is good stuff. For me its not a cost effective solution.