If you have used steel wool & sandpaper wow steel wool is not too bad if done lightly it will knock off worst of the rust, once you scratched it with sandpaper, sounds like a replacement item. You have to remember if you remove rust from chrome you often end up with black patches, which are in same ways worse. I've just cleaned a load of rusty chrome steel racing mud guards up amazing how much came off with suitable polish, but it left black areas.