Educate yourself about car polish
Car polishing is in fact being commercially used before the 1930's. Due to the mass commercialization and the popularity of car polish, it is readily available in stores. It will not be an oversimplification to suggest that the car polish is a variant of sand. In fact the sand also shines the surface but the only difference between the two substance lies in the abrasive nature of the car polish which makes it stick, harden and shine, at the same time. Certain natural colors like red are exposed to the natural sunlight that makes them vulnerable to rust.