Rust-Oleum Whink Rust Stain Remover | Heavy-Duty Iron Stain Remover Foaming Spray with Excellent Cling for Toilets, Showers, Sinks, Outdoor Siding | 24 oz

Absolutely works to get hard water/rust stains out but has a very chemically smell. The spray bottle didn't work so I ended up pouring it out onto stains instead

On cement - turns white if not careful

This product really whitened my quartz-kitchen sink, but did nothing for the porcelain sinks and bathtub. Caution: The bottles were well-packaged with tape around the necks of the bottles and each bottle was in a separate bag BUT they all still leaked. The shipping box was stained and each bag was wet. The product stung my hands upon removing the packaging. Also, the sprayers are difficult to use. It took forever to get any product out of the bottle and there is a stream-spray that doesn't cover much area. I prefer a wider spraying area. You also need to know that this product has a strong, toxic odor. You can barely stay in the room after spraying it.

At our house we have well water that stains everything it touches. Tubs and toilets are almost impossible to clean even scrubbing with iron out and scotch bright pads never worked. Let me say this is the most amazing thing I've ever used on both of them. Had to spray twice but all stains are completely gone without doing anything but spraying it on and rinsing it away. If you've struggled with this type of problem this is the product that works. It will stay in my cabinets from now on.

This is the best hard water rust stain remover I've ever tried Amazing !