I tried this on a whim, just to see if it worked and I'll be damned did it ever. I used a small battery charger, a 5 gallon bucket and short rebar rods placed around the outside. Filled it up with water and baking soda (couldn't find any baking powder local) and it worked excellent! I wonder how well it would work if I did it right?
It works best on pieces that are absolute balls of rust. It cant make metal appear when it's already gone but it does make all the rust go away eventually.