Cleaning system for coffee machines and similar devices, in the cleaning circuit of which a cleaning key having a storage chamber is installed for receiving appropriately configured cleaning tablets. The cleaning key can be turned in a sleeve-like housing into two operating positions at defined angles of rotation, wherein in one operating position the storage chamber is fixed in the housing while in the other operating position, the storage chamber is released and can be removed from the housing to be filled or refilled with suitably packaged cleaning tablets.