Copper has a warm, gold brown color, like a new penny when its new. Copper is a living element which reacts to its environment, creating a greenish-blue patina as it ages. Although some people like this look, others prefer to preserve the original color. Preserving the original color requires removing the oxidation and then sealing the copper to protect it from the elements. There are several methods you can employ to remove the tarnish and restore your copper items to their original glory.
Removing Copper Patina
Place a pot filled with water on the stove. Add 1 cup of vinegar and 1 tbsp. of salt. Submerge the copper item in the solution and boil for several hours on the stove, topping up the water as needed. The vinegar and salt form an acid which eats away at the tarnish. Remove the pot from the stove and allow the copper item to cool. Wash in warm soapy water and dry with a soft cloth.
Use a cleaning paste if the item is too big to boil. Wash the item with warm soapy water, rinse and dry with a soft cloth. In a small bowl, mix equal parts of salt, vinegar, flour and enough water to make a paste. This is a great cleaning paste for mild tarnish. For severe tarnish, mix equal parts of lemon juice and salt or use tomato paste. Apply the appropriate paste with a soft cloth. Rinse with warm water and dry with a clean, soft cloth.
Apply a commercial copper cream to remove the patina. Copper cleaners are readily available from supermarkets and home maintenance stores. Read the instructions carefully to ensure that the product is suitable for your copper item. Using a soft cloth, gently apply a generous layer of the cream onto the copper item. Allow to sit for a few minutes and then buff the item with a clean, dry cloth.
Preventing Copper Patina
Coat the copper item in a protective coating to prevent future discoloration. Coat the item in beeswax or carnauba wax. Dip the soft cloth in the wax and apply it to the copper surface. Buff with a clean soft cloth.
Apply two thin coats of linseed oil using a soft cloth. Buff the surface until it shines. This is particularly useful for outdoor copper items.
Cover the copper item with a lacquer finish. Use a soft paint brush to apply the first coat. Allow to dry. Apply the second coat and leave it to dry.