What is an effective copper cleaning solution?

Lemon juice and salt effectively cleans copper pans, and a mixture of lemon juice, cornstarch and salt removes tarnish. A mixture of baking soda and lemon juice also effectively cleans copper.

Commercial copper polish is also available, and is used according to the directions on the product packaging. When cleaning copper with a baking soda or cornstarch paste, wash the item in warm water and vegetable-oil based soap, such as Castile soap, after polishing. To clean copper pans, pour salt onto a lemon wedge, and scrub the pans with the lemon before washing and rinsing as usual. Dry the copper item immediately after washing.