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.
- Gather the materials
Get a bottle of ketchup, baking soda, a toothbrush, a small bowl and a dirty penny.
- Apply the ketchup
Rub a small dab of ketchup on both sides of the penny. Lightly scrub it into the penny with the toothbrush.
- Rinse the penny
Rinse the ketchup off the penny with running water.
- Make and apply the paste
Pour baking soda into the bowl. Add enough water to make a thick paste. Rub it into the penny with your fingers.
- Remove excess paste
If any paste is left on the penny, gently remove it with a soft cloth.