Most people are proudly display their copper cookware by hanging it on hooks in the kitchen. But that pride can quickly fade, as the pots start changing color. Exposure to heat, air and humidity can very quickly change the appearance of copper. This process is called oxidation, and it happens when the copper combines with the oxygen and moisture in the air and loses some of its protons. This causes the color of the metal to change to a deeper orange. Oxidation can also cause copper to develop purple and blue streaks. If you leave it unchecked for a long period of time, oxidation will result in blue-green "salts" growing on you copper cookware [sources: American Chemical Society, Britannica]. Cleaning copper like a professional is easy and doesn't require complicated techniques and expensive chemicals. Here's how to clean copper cookware and copper coins.
- Sprinkle salt on half a lemon. Rub the salted side of the lemon on the tarnished area. The salt will act as an abrasive and the lemon will act as the cleanser. The combination will clean the tarnished area.
- Squeeze a lemon and add some salt to the juice. Pour the mixture onto a cloth. Rub the mixture on the pot. Again, the combination of salt and lemon juice will clean the area.
- Fill a large pot (larger than the tarnished copper pot) with water. Add salt and vinegar, and bring the mixture to a boil. Place the copper pot in the solution. Leave the pot in the boiling solution until you see the tarnish disappear. Rinse the copper pot with warm water.
- Make a paste of salt and vinegar.
- Rub the paste on the coins with a tooth brush. Let the paste sit for a while. If the coins are very tarnished, leave the paste on overnight.
- Wash the paste off the coins, and they'll look like new [source: Martha Stewart].