It is best not to store acid foods in aluminum or other metal containers for long periods of time. Copper Copper is often used in cookware because of its good heat conduction properties. Most copper cookware is lined with tin or steel so there is little chance of copper migration into the food. Copper cookware that is unlined or has lost the lining due to repeated use should not be used in food preparation. Antique copper cookware is often unlined and should not be used.
Some new copper has a protective coating that prevents discoloration.
This outside coating must be removed before using to prepare food or heat. Refer to manufacturer's directions for removal. Pottery or Ceramic Pottery or ceramic cookware should be made especially for food purposes so that any lead in the glaze does not migrate into food. If a pottery or ceramic piece is not specifically manufactured for food purposes it should be considered a decorative piece only. Even in properly manufactured pieces acid foods should not remain in them for any length of time.