Abstract: An apparatus and method are provided for handling the problem of crud formation in solvent extraction equipment. "Crud" is the name commonly given to the thick interfacial layer of semi-floatable material that accumulates and interferes with many solvent extraction operations.The apparatus disclosed is used in combination with mixer-settler equipment, and it includes a rotatable shaft, a blade mounted on the shaft, apparatus for moving the shaft and blade across a plane parallel to the surface of the liquid inside a rectangular settler vessel, equipment for rotating the blade and shaft about the shaft's longitudinal axis, and a locking device for locking the blade into an extended or retracted position.