You will need
  • - lemon;
  • - flour, salt, and vinegar;
  • - vinegar and hot water;
  • - tooth powder or paste;
  • liquid for cleaning jewelry;
  • - cloth;
  • - toothbrush;
  • - old newspaper.
Take half a lemon, the flesh insert a coin and let it a little "soak". After about 15 minutes, remove it and clean with a brush. Rinse in cold water and dry with a soft cloth.
Mix a little flour, coarse salt and add a splash of vinegar. Well RUB the coin in the mixture and wait a while and rinse in clean running water. Be sure to wipe the copper dry, otherwise dark spots are formed almost immediately.
Dilute the vinegar in boiling water. The approximate concentration of acetic acid should not exceed 20-25 %. Add 2-3 tablespoons of table or sea salt and dip the coin into the solution. When the water with the vinegar has cooled, carefully remove the coin and clean with an old toothbrush. Rinse in clean water and wipe with a cloth. Be careful when working with a concentrated solution of vinegar, you can get poisoned by fumes.
If you have tooth powder, use it, and if not, you can use a regular whitening toothpaste. Wet the coin and RUB it with the paste or powder, the active movements of the brush. Rinse and look at the result if you are not satisfied, repeat all over again.
Liquid to clean jewelry is also able to bring back the original look of copper. Buy the tool at a jewelry store or in the workshop, drop a coin for a few minutes and wipe thoroughly with a clean cloth. If you fear for the integrity of the coin and I'm afraid to clean it yourself, please contact the jewelry shop. You will produce professional cleaning and polishing metal, is also cause and a special clear coating that will protect the copper from darkening.