Abstract: The invention uses the electro-kinetic principle for a method for the cleaning of materials contaminated with heavy metals, whereby use is made of an apparatus comprising two charge-selective ion-exchange membranes with different charges combined with an inner and an outer electrolyte solution chambers which are separated by the membranes which serve a blocking function. A surprisingly good degree of removal is achieved, particularly in relation to the current consumption, and at the same time the heavy metals can be precipitated in a separate vessel such that they can be reused.