Brass & Copper

Copper The finest antique copper pieces are very heavy, show little wear, and have no dings or dents. The color should run to red rather than pink, which is a sign that the piece is new and probably has an aluminum core. Copper cookware should always be lined with tin, stainless steel, or some other nonreactive metal to prevent the potentially toxic reaction that occurs when acidic foods come into contact with copper.
Brass-This alloy of copper and zinc tarnishes easily. Most pieces made after 1940 have been coated with lacquer to prevent the metal from oxidizing and going dark.