Another thing to consider is that ANY acid based rust remover ALSO removes the metal itself, at the very least you'll end up with an acid etched surface. Consider this if you are trying to preserve any of the original part surface appaearance. If the surface is a concern stick with a product like Evap-O-Rust that destroys rust and leaves all other materials (metal, paint, etc, metal finishes, etc.) 100% intact.