Once metals are cleaned, metallurgists use microscopes to examine minute details of the metals in order to reveal information regarding composition and manufacturing techniques. For example, the artifact shape, cracks, and places where pieces of metal were joined together can be identified. Additionally, one garner information pretianing to casting errors, mould seams and decorative work. Metallography exams the size and shape of the grains of minerals in the materials for traces of heating, working and alloying. Scanning electron microscopes are also utilized to explore manufacturing techniques used for jewellery and weapons making. This is because they enable fine detail to be identified, such as when they examine the hammering of folded layers of metal to create a sword. Additionally the identification of the marks of the tools that were used to make the artifact can inform studies of manufacturing techniques. Also, other techniques are used to identify types of metals. For example, Atomic absorption spectroscopy is used to identify alloys of gold, bronze and copper. However, this is not as effective if an artifact contains multiple types of metals.