Puro Caff is a specially designed cleaner for espresso machines. It removes the residual build up of coffee solids and oils from screens, valves, and tubes of brewing groups. Backflush your machine following directions on label, and soak the portafilters in a solution of very hot water and Puro Caff. Thoroughly rinse groups and portafilters. Always re-season your machine and portafilters by making and discarding one espresso on each group. Espresso machines should be cleaned daily.