WADR, if you are going to remove the "red " rust, first dip the part in some kind of heavy oil, or put oil on the surface. Then, dip the 4-O Steel wool in the oil and LIGHTLY rub the rust. Red Rust is IRON OXIDE, and it capable of stractching and abrading the other metal. By using oil often to rince the rust from the steel wool, you will help to remove JUST the RED RUST, and nothing more.
The RED RUST will appear to cover more surface area than it really does. When the rust forms, it " blossums" like a flower, actually growning above the surface and opening up and out. That is why it comes off on your hands so easily, just by picking up a piece of rusted iron.
You will be surprised how much original finish or patina can be " saved" by simply taking your time, and being very gentle with how you "rub" the metal to remove the rust. :thumbsup: