There are many ways to clean a copper penny, but one method is to scrub it with ketchup, rinse the penny with water, and buff it with a paste of baking soda and water. Wipe any remaining paste away with a soft cloth.Continue Reading
Get a bottle of ketchup, baking soda, a toothbrush, a small bowl and a dirty penny.
Rub a small dab of ketchup on both sides of the penny. Lightly scrub it into the penny with the toothbrush.
Rinse the ketchup off the penny with running water.
Pour baking soda into the bowl. Add enough water to make a thick paste. Rub it into the penny with your fingers.
If any paste is left on the penny, gently remove it with a soft cloth.