Abstract: A method is disclosed of protecting a land or roadway vehicle body from surface corrosion which causes pitting, blistering, and other defects in paint at the joints in the skin, where the body surface is comprised of dissimilar metals in its skins and stringers and in the fasteners therefor. Roadway vehicles such as ambulances and fire trucks often have aluminum skins fastened with stainless steel screws, bolts, or rivets to aluminum structural members to save weight, but corrosion thereof is a persistent problem. The new method comprises using an anti-oxidant, a heavy grease compound with metallic zinc dispersed therein as dust or powder, such as electrical joint compound, as a bedding compound applied to surfaces of the fasteners or to the insertion apertures therefor before assembly. In one commercial form, the compound comprises about 51-53% by weight zinc, about 36% by weight refined heavy paraffinic distillate, and about 11-13% by weight aluminum stearate.