I'm using Aircraft Paint Remover now on steel wheels and body panels, and it's plenty strong and working very well. As long as you put it on thick, the paint will craze and lift up in a few minutes. It has a very strong ammonia odor, and it will chemically burn your skin pretty quick if you don't wash it off, so it's potent stuff.

My body and paint shop advised me to use Aircraft and to coat afterwards with Rust Cure or other phosphoric acid and wipe down with mineral spirits to lessen the acid residue.