(1) If the "white rust" is found to be white in color, it can first be washed off with water, then the zinc layer should be dried with a cloth. After that, apply a slurry made of talc powder and caustic soda with a brush onto the surface.
(2) If the "white rust" has turned dull in color, a water solution of potassium acid tartrate and ammonium carbonate can be brushed onto the corroded area. Then, use a sponge soaked in calcium carbonate to wipe it off. Finally, rinse with water and dry.
