if your doing a "true" rat look, you don't rub any rust down you leave well alone, scotch bright is like the green plastic brillo pads that you use on your pots and pans, you rub that all over the paint that's left to just key up the paint so that the laquer will stick to it, the laquer is normal 2k with matting agent to make it go dull, this is then painted over the whole body to seal it and stop it getting worse, another trick used by ratters is just cooking oil all over it to stop it rusting
