Abstract: The invention provides an apparatus comprising a container having a bottom wall and a side wall extending upwardly therefrom to define a first chamber that is rotationally symmetric about an axis throughout a major portion of its perimeter and a second chamber in communication with the first chamber, a divider rotatably receivable by the first chamber and having a shaft and a plurality of fins extending from the shaft toward an inner surface of the side wall, a first-chamber cover adapted to be received by a top edge of the container side wall to provide an upper surface for the first chamber and defining a hole for rotatably receiving the shaft.