Eastwood Rust Dissolver removes only the rust, and won\'t eat-away at the metal itself. Leaves the newly de-rusted metal ready to paint, plate or powder-coat. Gentle enough for engine parts Reusable Removes about 5 sq. ft. of rust per quart Liquid rust Dissolver works as long as the surface is wet. Items that cannot be fully immersed due to size can be placed in the discharge stream of a commonly available small pump. One gallon de-rusts about 20 square feet of metal. This product is not safe to use on aluminium.