1 soft cotton cloth
Bicarbonate of soda (baking soda)
Dampen the cloth and add a small amount of baking soda (less than 1 tablespoon should do).
Place the article to be cleaned on the cloth and wrap the article in it. Rub gently, moving the article around in the cloth to remove the tarnish.
When the article is clean, rinse well in running water and dry.