Abstract: A support structure is provided for recessing below the upper surface of a floor or walk and an elongated horizontal grill is mounted from the support structure and includes a plurality of elongated horizontally laterally spaced apart grill members spaced longitudinally along and extending transversely of the grill. The grill members are free of interconnecting structure throughout substantial portions of their length aligned longitudinally of the grill and a pair of parallel rollers are journaled from the support structure and spaced beneath the grill with the rollers extending longitudinally of the grill and transversely of the grill members. A wide endless flexible belt is trained about the rollers and includes outwardly projecting bristles projectable upwardly through the generally vertical slots defined between adjacent grill members. A motor is supported from the support structure and drivingly connected to one of the rollers whereby the belt may be orbited about the rollers.