Abstract: A pre-soak station, a washing station, and a drying station are arranged in an in-line manner so that a multiplicity or group of mold support units or workpiece holders arranged single file may be moved sequentially from station to station. A first group of such units after being submersed in a hot water/detergent bath at the pre-soak station is placed on an open rail support or trackway for conveyance to the washing station where nozzles supported on corresponding manifolds surrounding the trackway direct pressurized streams of hot water against the individual units for a predetermined interval or washing cycle.