Abstract: The removal of bonded sand, either core sand or mold sand, from a metal casting comprises placing the metal casting in a furnace chamber and subjecting the metal casting to the action of a high velocity heated gas stream (preferably above 3000 ft/minute) from hot air generators positioned on opposite sides of the chamber at the approximate level of the metal casting and directed to the metal casting. The heated gas stream is at a temperature and oxygen content sufficient to oxidize the binder in the bonded sand and a velocity sufficient to remove the debonded sand. The sand is removed by gravity from the furnace chamber.