Unknown.
DCL
Set your copper pots, utensils, and fixtures all agleam, without resorting to pungent industrial solvents. It couldn't be easier: Mix some fine table salt with the juice of half a lemon. Dab the mixture onto the copper surface with a dry cloth and rub it in using a circular motion. Rinse the surface off with water, then buff it to a shine with a soft rag.
If that doesn't do the trick, you can also boil your article for several hours in a pot of water with a tablespoon of salt and 1 cup of white vinegar.
Difficulty level: Easy
