Home >> Collecting >> Coin Collecting

How to Take Copper Plating Off Zinc Pennies

The humble penny has been made from many different metals over the years including steel, brass and bronze. From 1962 to 1982, American pennies were made of brass, a mixture of mostly copper and some zinc. However towards the end of that time frame, the cost of copper increased significantly, so pennies minted since 1983 are made up of a zinc core coated with a thin layer of copper. This copper makes up about 2.5 percent of a penny by weight. It is possible to remove the copper coating using a strong acid, providing that proper safety precautions are followed.

Things You'll Need

U.S. pennies minted since 1983
Gloves and safety glasses
Chemical fumehood
Glass beakers
Concentrated nitric acid
Water
Tongs
Toothbrush and toothpaste

Instructions

- 1
  Fill a small glass beaker with enough nitric acid so that you can completely insert a penny. Fill a larger glass beaker with plain water. Label the beakers to show their contents. Both beakers should be in a functioning chemical fumehood to remove toxic vapors.
- 2
  Grasp a penny with the tongs and dip it into the nitric acid. Immediately remove it and insert it in the rinse water beaker. Repeat this process until all the copper is removed. You may need to change the position of the tongs between dips so the entire surface of the penny is exposed to the acid. Do not keep the penny in the acid too long and do not continue to dip it after the copper is removed because the acid may start to attack the zinc core.
- 3
  Rinse the penny under running water to remove all traces of acid. Scrub with toothbrush and toothpaste to shine and polish the remaining core.

Coin Collecting