A process for heat treating an anode casing of a zinc/air depolarized cell after the casing has been formed but before anode material comprising zinc is inserted therein. The anode casing has a layer of copper on its inside surface. The process comprises heat treating the anode casing by passing a gas at a temperature between about 200° C. and 700° C., preferably between about 300° C. and 600° C. in contact therewith to form a heat treated anode casing and then cooling said heat treated anode casing to ambient temperature. The heat treated anode casing is stored away from atmospheric air until anode active material is inserted therein during cell assembly. The heat treating process significantly reduces gassing during cell discharge and storage and eliminates the need to add mercury to the anode material.