Rust Bullet (sp?) is an alternative/competitor to POR15 (mentioned above), & for stripping mechanically, there's an attachment for a drill which often times works better than a wire wheel
. It's made of some grey synthetic, & as some of my men
(when I was an Ensign) dubbed it, looks like pubic hair - so they came to call it Bionic Pubic Hair. But they work well for stripping; paint, rust, & various other things.
Plus, given that it's non-metallic, there's no iron/steel residue left, once you're finished, to rust. Unlike with wire wheels, some sanding
agents/papers, grinders, etc.