OVEN CLEANER-4021 can be sprayed, as with a garden sprayer, or manually applied by brush. The amount of material required, setting time, and the amount of mechanical agitation needed will depend upon the severity of the build-up and the plants' operational constraints. Rinsing of this product can be accomplished using either high or low-pressure water spray. Since OVEN CLEANER-4021 contains caustic, care must be taken to insure against attack on soft metal surfaces like aluminum, magnesium, or galvanized metals. When working on such substrates, the contact time after soil removal from the surface should be kept at a minimum.