Muriatic is nasty stuff ,and will probably keep on eating away at the metal..get any on you,you dissolve too!..its better for taking splatters off cement or bricks that metal ,its corrosive..
I have not used enough of the many different kinds of rust killers to say this one works better than brand X does--but when I sold that kind of stuff at a parts and auto paint store,the body shops liked Rust-Mort the best,and the R-M paint brand of phosphoric acid rust killer..
I tried both and thought they worked well..
I have also used Duro/Permatex "Extend" that is a latex based rust converter that goes on looking like milk--then turns any rust black ,it dries to a transparent amber on non rusted surfaces..it does keep rust from returning well for a long time..
I have used Rustoleum "Rust Reformer" and its about the same deal..
Some clain a can of coca-cola or other drinks laced with phosphoric acid works too,but the sugar presents a problem,it'll make a sticky mess and paint wont want to stick well to it..washing it off encourages more flash rusting...
I've used white vinegar to etch a galvanized trash can so the paint wouldn't flake off it and it worked..not sure if it will "convert" rust,but it will probably dissolve it if exposed long enough..
