Rust is like a nasty cancer. It's not so much that you stop it, as it is you manage it. Stop managing it and it will come back.

The only way to actually get rid of it is to either cut it all or sand blast it all off and repaint. And even then, your chances aren't great. It starts in the little pockets and tight corners up underneath and inside the body and works it's way out. Once it's showing on the outside, it's almost too late to remove it all. It almost requires a complete tear down and repainting of the vehicle.

I've tried a bunch of those navel jelly's and "rust inhibitors" and I've never seen anything that actually worked. As best I can tell they just hide it for a short period of time. Sanding, grinding, scraping and cutting are the only ways to actually get rid of rust.