If you want to really remove the rust by converting it back to good metal instead of just sanding it off, you have to use electrolysis.
Electrolysis does not, "convert rust back to good metal". It turns it into a black, soft, material that can be easily removed with a wire brush. The metal that is left after the black crust is removed is clean and bright. There well however, be pits left from the rusting process...there is not way to avoid that because when rust forms its volume is greater than the metal's was. consider the following: Fe is iron. O is oxygen Fe2
is rust. If one could convert rust back into iron, one would have to use a chemical reduction process (if I am not mistaken), by combining Carbon monoxide with the rust. Fe2
+ CO =2Fe + 3CO2
This is generally what happens in a smelter, they add iron ore (rust) to coke (adds carbon and carbon monoxide when it burns, just as charcoal does.) I probably screwed up the balance of the equation, but that is generally how it goes. But, if I am wrong, chemistry majors, please straighten me out on this.