I don’t think you’ll ever get rid of it completely, but this how to treat and prevent rust.
Take a wire brush or a finishing sander and clean off the rust as best you can until you get down to the orange core of the rust at the bottom. Brush away the powered rust residue and treat the surface with a liquid rust converter. This will turn the rust black, or back into a quasi metal (rust converter).
Then, what I do, is apply 1-3 coats of Rustoleum’s Rusty Metal Primer, and then apply 1-2 coats of Rustoleum’s Satin Finish. The more coats the better protection.