Use a jewelry polishing cloth to clean copper jewelry. Gently rubbing the jewelry piece with the cloth will most often restore the shine. You can purchase a polishing cloth at most jewelry stores.
Cut a lemon in half and add a dash of salt to cut side. Rub the lemon over the jewelry piece. You can also add a dash of salt to some lemon juice (enough juice to coat the piece). Dip the jewelry into the juice and let it sit for a few minutes. Rinse the piece off with water and dry it thoroughly with a polishing cloth. Rub your jewelry with a small amount of ketchup or tomato juice. Rinse well and dry with a polishing cloth. Combine equal parts of lemon juice and baking soda to form a paste and rub the paste on your jewelry. Rinse and dry. Sprinkle some Worcestershire sauce on your copper piece. Rinse well and dry thoroughly. Grapefruit juice, vinegar and anything else mildly acidic will clean your copper, but lemon juice generally works best.
To keep you copper jewelry from tarnishing, store the pieces in a jewelry case or re-sealable plastic bag, and use anti-tarnish paper. Don’t wear copper jewelry in swimming pools or hot tubs. The chemicals in the water can damage your jewelry. Your copper pieces will maintain their luster if you treat them with care: wipe off your jewelry with a polish cloth after you have worn it. You can also clean it occasionally with a mild detergent and water.
You can use commercial cleaner, but before you do, make certain that this products will not do any damage to any stones your jewelry contains. Surprisingly, the tomato acid found in Worcestershire sauce is an excellent choice for cleaning copper jewelry, but it also should not be used with pearls or delicate stones that could not withstand commercial cleaners. Ketchup also does a good job, but it is less convenient to use. You can apply it with a soft cloth or old toothbrush and then rinse the jewelry well, but take the same precautions that you would with Worcestershire sauce.
You can also combine water with lemon or lime juice and a teaspoon of salt, and stir the mixture gently. Allow the items, which should not be in the delicate category, to soak in this mixture for just a few minutes. Then remove them, and be sure to rinse the jewelry thoroughly. If required, you can also repeat the process. Make sure your jewelry pieces are completely dry before you put them away. It’s a good idea to store your copper jewelry in an air tight box or in plastic, re-sealable bags to keep the air and humidity from tarnishing them. Don’t let lemon juice or any other acidic substance come into contact with stones that may be embedded in the jewelry piece.
Use a jewelry polishing cloth between cleanings to keep your jewelry shiny. * The above tips are from www.wikihow.com
Our favorite cleaner is called TARN-X and is available at most all grocery, hardware, Walgreen's and CVS stores. Works great!