This descaling powder is usually used by mixing the powder in the water tank. For espresso group head cleaner check here. General descaler for most coffee machines 6x 25g. Contains a synergistic blend of organic acids that give outstanding scale removal. Renew is Listed with NSF. It has been tested, evaluated and passed the most stringent toxicology and corrosivity standards. The ingredients and formulation of Renew are safe, leave no harmful residues and do not cause corrosion within the coffee machine. Safe to use on aluminum, brass and stainless steel. Designed for espresso machines, boilers and coffee brewers. This product can also be used in kettles, urns and bain-maries.