Abstract: The mixing pistol for reactive multiple component materials includes a self rotating mixing rotor in a mixing chamber, and several valves controling the injection of a component into the mixing chamber. Additionally there are valves for the injection of cleansing solution and compressed air. While cleansing the mixing chamber, in order not to have to remove the used cleansing solution by way of the outlet of the mixing pistol, which would be connected with the removal of dangerous and harmful fumes and gases, there is an additional outlet valve arranged at the mixing chamber by means of which the removal of the used cleansing solution is accomplished. The cleansing solution is driven in the mixing chamber in a closed circulation and never comes into contact with the outer region of the mixing pistol.