I use CLR on rust stains in my shower encloser. NOTHING!!! did not even budge the stains. I am very displeased with your product. I left it on for the required time, then longer, then longer. Did not do anything. I used Iron out. It has a bad order but one application and gone. I used CLR on the corrosion on the drain. Nothing happened. I wasted money again. Tried this a few years ago, thought I would give it a second try. Bad idea. Use it on tv, that is about the only place it really works.