(статья на английском языке)
Here are some easy ways to clean copper with things easily found in any kitchen, and readily available at any store. Using vinegar and salt:
Pour vinegar and salt over copper. Keep rubbing in to remove any tarnishing and grime. Rinse off. Polish it up with a soft, clean, dry cloth.
Place 1 tablespoon salt, and 1 cup white vinegar into a large pot and fill it with water. Place your copper item into the pot. Bring it to boil and continue boiling until the tarnish comes off. When you are satisfied remove the item and dry it after washing in hot water with a bit of soap.
Cut the lemons you will be using in halves. Rub them over the tarnished areas until you are satisfied than rinse and polish.
Using lemon and salt. Squeeze lemon juice from 1 lemon and mix it into a paste be adding salt. Rub the paste over the copper with a soft cloth. Rinse off with warm water and polish the copper.
Spread ketchup over the copper item and let it sit for a few minutes before washing away. Ketchup can be messy, but it is a good alternative as any.
сopper — медь
vinegar — уксус
tarnishing — тусклость
grime — глубоко въевшаяся грязь
to rinse — промывать
to boil — кипятить