Chisel Water Stain Remover in quarts is an awesome product for removing hard water and rust from toilets, urinals, sinks, tubs and drinking fountains. It works like magic on removing rust, silica, iron, scale - no matter the mineral Chisel will attack it. Switch to Chisel and watch those rings disappear. Works great on those stubborn rings that appear on the water line inside your toilet bowl and the residue around faucets where the water stands and dries. Brown, green, yellow or orange... Chisel removes it all. Use only as directed and always remember to use the proper PPE and only let set for 1 - 2 mins before scrubbing and rinsing away. Not to be used on glass or soft stones such as marble as these surfaces can quickly be chemically etched.