For fully automatic washing machines: Pour 1 packet of powder into the machine drum and run the longest program, without any clothes, with the temperature between 40–60˚C. Once finished, clean and refix the fluff filter. Run the rinse program with plain water.
For showerheads: Detach the showerhead or remove the sprinkler nozzle. Dissolve 1 tablespoon (15 g) of the powder in a plastic mug filled with hot water and mix it with a wooden/plastic spoon.
Leave the solution till the effervescence stops.