Removes rust and hard-water scale from tank and heating element. Cleaner is a safe, biodegradable, stable powder that removes rust and hard-water scale from the machine's tank and heating elements, keeps the steam machine running smoothly and efficiently, and helps prevent burnout of fouled heating elements. Powder is dissolved in water, added to the machine, and run through the usual steam cycle. Deposits are dissolved and then flushed away. Contains no mineral acids or caustic alkalis. About 6 treatments per tub. 1 Lb. tub with convenient measuring scoop.