A protective coating is a layer of material applied to the surface of an object to protect it from damage or corrosion. Two common types of protective coatings are ENAMEL and WAX. ENAMEL is a type of paint that is usually made of a combination of resin, oil, and pigment, and is often used on metal surfaces. WAX is a natural or synthetic substance that is applied to surfaces to create a protective barrier against moisture and dirt.