A method of casting metals in which the desired form was carved in wax, coated with clay and baked; the wax runs out through vents left in the clay for the purpose, and molten metal is then poured through the same vents into the mold. When the metal is cool, the clay is broken off to reveal the metal casting. Each mold can only be used once. The technique was first developed in the 4th millennium BC in the Near East, especially by the Shang bronzeworkers of China. It was also used for gold in South America and Mesoamerica. The method was used for casting complex forms, such as statuary.