How to remove rust from steel security door?

http://www.doityourself.com/stry/removing-rust-from-metal-doors

Try Brasso its a abrasive. Ifs real bad u will need a wire brush the use steel wool.

Rust-Oleum! You won't have to remove the rust, just lighly spray the screen so you don't plug the holes. If you want, you can hit it with a wire wheel on a hand grinder or even a wire brush (with some elbow grease) but it's not necessary

If you can't remove the door, repeatedly spray with white vinegar and let it soak and dry. Then scrub with steel wool or a stiff brush and rinse. As a previous poster suggested, a light spray with Rust-O-leum should do the trick. My Dad, a retired Air Force Crew Chief, learned the white vinegar trick back in the '40s and used it to remove rust and general gunk from all sorts of stuff. He's up in the "Wild Blue Yonder" now, and the vinegar trick is something I pass on whenever I can. It's simple, cheap and effective.

Brasso is amazing!