Science with Shields – Episode #6: Green Pennies


ALTOONA, Pa. (WTAJ) — In this episode of Science with Shields, Christy Shields shows you how to clean your pennies and also turn them green.

What you need:

  • Dirty pennies (before 1982)
  • White vinegar
  • Table salt
  • Paper towels or cotton pads
  • Small bowl
  • Saran Wrap
  • Container with lid


Part 1

First, you want to sprinkle table salt into a bowl to cover the bottom of the bowl. Next, pour the white vinegar into the bowl. About 1/4 cup should work. You’ll want to then drop your pennies into the mixture for about a minute. Tada! They are shiny! Rinse them with water.

Part 2

To start, you’ll want to wet a cotton pad or paper towel with vinegar. Next, stick the cotton pad into the container with the lid. Put a cleaned penny in and close the lid. You’ll then want to take another paper towel and dip a penny in the vinegar mixture and mark it with a V for vinegar. Take a rinsed penny on a different paper towel and mark it with an R for rinsed. You’ll then want to observe the pennies over 8 hours or overnight. Take a before and after photo to compare the difference!


Pennies are made of copper, so when copper interacts with oxygen, it creates Copper Oxide. The penny looks dull because over time, it was covered with copper oxide.

Salt and vinegar are acids, so is lemon or orange juice. Copper oxide will diminish when put in an acid.

Un-rinsed pennies will turn a blue-green hue. This is due to the layer being dissolved, which makes it easier for copper and oxygen to interact quicker. You add in the chlorine from the salt, and you create malachite. Malachite is a mineral.

Tune in on Tuesday’s at 10:30 a.m. for more Science with Shields experiments you can try at home.

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