Abstract: A rotary switch is mounted in a housing having a hollow interior. The rotary switch includes a shaft, which rotatably extends through a male threaded mounting. The rotatable shaft defines a bore which extends from an inlet defined on an exterior surface of the shaft, through a length of the shaft. The bore communicates with an outlet defined in the exterior surface of the shaft. The outlet is disposed within the hollow interior of the housing, while the inlet of the bore is positioned external to the housing. The bore defines a passageway within the body of the shaft through which a cleaning fluid may pass. The inlet of the bore is covered by a knob which is removably secured to the shaft. A first contact is connected to the rotatable shaft. A second contact is disposed within the interior of the housing for contacting the first contact. The first contact is also disposed within the interior of the housing. The bore may be used in cleaning the contacts positioned within the interior of the housing.