LIME OUT® heavy-duty rust, lime and calcium stain remover easily dissolves the toughest hard water and rust stains. Made by the makers of Iron OUT®, the heavy-duty rust removal experts, this product is specially formulated to dissolve tough lime, calcium and rust stains caused by hard water. An effective hard water stain and limescale remover, its thick, fast-acting, concentrated formula is great for use on vertical surfaces as it clings longer for maximum cleaning power. An excellent option for cleaning hard water deposits, LIME OUT is septic-safe and also safe for a variety of both indoor and outdoor applications.