Use 2 tablespoons of tartaric acid stirred into 4 ounces of warm water for a quick and easy descaling solution. Within 30 seconds of contact, the deposits will dissolve and you can dump the solution out - or store it for the next use! To descale espresso machines, you merely run the tartaric through your system and dunk the steamer in the solution.
Your products scale because excessive calcium and sodium (a base) has deposited onto the metal. When a base reacts with an acid (the tartaric, in this case) it is freed from the metal very quickly.