Brass is a metal alloy, which means it is a mixture of two or more metals, usually copper and zinc. The metals are heated until they melt. They are mixed together, then allowed to cool down and harden. Brass is graded according to the metals used and the percentages of each component, which may determine differences in its properties and usage. The various brass alloys are used in machine and electrical components, musical instruments, architectural decoration, trophies, plaques and jewelry. It is easily stamped, shaped and drawn and is a good conductor of electricity.

Look at the color of the brass. The more copper in the brass alloy, the more red will be the color of the brass. Brass used in jewelry and decorative architectural features is graded as CZ101 and has 90 percent copper content and 10 percent zinc. It is soft and almost red like copper in color. CZ102 brass contains 85 percent copper and 15 percent zinc. It is also red or may be a little more tan. This alloy is used mainly for architectural decoration like door handles and decorative trim.

Consider how the brass is used. Brass is the metal alloy used to make most bullet casings. Graded as CZ106, this brass, known as "cartridge brass," has a green-gold color. It contains a 70/30 mix of copper and zinc and is easily drawn or hammered into different shapes. CZ108 is known as "common brass" and is used to make machine and electrical parts. It is a yellow color and is a 63/37 alloy mix. "Low brass" or C240 is the yellow-gold alloy used to make musical instruments. It may contain 0.05 percent iron and lead.

Find out if it is to be used for engraving. The alloy known as "engraving brass" is a little lighter yellow in color and contains 59 percent copper, 39 percent zinc and 2 percent lead. The small percentage of lead makes this alloy easier to machine and form into thin brass sheeting to make plaques. Small percentages of other metals, including tin and aluminum, may be added to a brass alloy for various purposes, but they are not easy to identify.