Abstract: An upwardly opening receptacle is provided including lower closure structure defining a central gravity flow outlet. A flexible drain tube includes an inlet end operatively associated with the outlet for receiving liquid therefrom and an outlet end. Structure is provided for removably mounting the receptacle in stationary position within a motor vehicle and the outlet end of the drain tube is routed through the vehicle body portion for discharging liquid drained from the receptacle onto the ground beneath the vehicle. A spray jet is operatively associated with the vehicle for discharging a spray discharge of flushing liquid into the receptacle and liquid delivery structure is operatively associated with the spray jet for supplying liquid thereto under pressure from a liquid reservoir supported from the vehicle.