Abstract: A generally rectangular upwardly opening receptacle is constructed of plastic and includes side and end walls incorporating transversely thickened zones thereof in horizontal registry with each other and defining a reinforcing belt extending peripherally about said receptacle along lower portions of the side and end walls thereof. The side and end wall portions disposed beneath the reinforcing belt are inwardly offset relative to the remaining upper portions of the side and end walls and define a horizontal inwardly projecting shelf extending about the interior of the receptacle upon which a grid assembly is supported, the grid assembly incorporating a first weight supporting lower first grid and a second finer grid overlying and supported from the coarse grid.