Mix salt and lemon juice together into a paste.
Apply the paste to the area of tarnish on the copper, rubbing it in vigorously.
Allow the paste to sit on the tarnished copper for 15 minutes.
Rinse the salt paste from the copper item and wash thoroughly in a dishwater detergent and water solution.
Dry the the copper piece completely and buff to a luster.
For severe tarnishing, apply a commercial copper polish according to label directions. Then, rinse thoroughly, wash and dry.
Make your own copper cleaner to avoid the harsh chemicals and expense of commercial copper cleaners. Mix 1 tsp. ammonia, 1 cup calcium carbonate (available at art and hobby stores) and 1 pint of soap jelly (made from 1 cup shaved soap melted in a quart of boiling water), advises University of Florida professor Marie Hammer. Rub the mixture onto the copper surface until the tarnish fades.