Well according to my knowledge the rust is thing which is not prefectly removable. So the best way to get rid of it is replace the whole panel. But if you think its expensive and you want you original one then here is the instructions for removing the rust from the panels. you can visit this link to know how to remove it. (wikihow.com/Remove-Rust-from-a-Car) Copy the underbracket url in your browser.