DIY | Penny Cleaning Experiments

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We’re going to take a look at some ways to clean pennies that kids can experiment with–not because there’s any great demand for clean pennies, but because it’s a chance to play around with experimentation and using the scientific method. Like so much in early learning, the focus here is on the process, not the finished product.

We’re going to look at five penny cleaning methods. We can attest to the fact that all five methods will lead to cleaner pennies, but we’re not going to tell you which one works best for two reasons. First, the answer is probably pretty subjective. Second, there’s no reason to give it a try if we tell you the answer.


Before striding ahead, let’s take a really quick look at what kids might learn while playing around with different ways to clean pennies. They are likely to learn or refine skills like:

  • Following directions
  • Asking questions
  • Understanding cause-and-effect relationships
  • Patience (letting a penny soak in lime juice for five minute may seem like it takes forever!)
  • Hand-eye coordination
  • Visual tracking
  • Muscle strength and control in the hand and wrist
  • Understanding chemical reactions
  • Language skills

Of course, they may also learn that cleaning pennies is boring and they’d rather be playing video games–one never knows. The point is, there’s lots of potential for learning STEM and other skills with these simple experiments.

Penny Cleaning Methods

The Tooth Brush Method

Dip toothbrush in water and use it to scrub a dirty penny. Then scrub some more. Rinse the penny with fresh water and set it aside to dry. It’s a good idea not to use your own toothbrush and an even better idea to use a discarded toothbrush.

The Salt And Vinegar Method

Mix one tablespoon of salt with half a cup of vinegar in a small container and stir until the salt dissolves. Next, drop in a dirty penny and stir. When the penny is clean, remove it, rinse it with fresh water, and set it aside to dry.

The Pickle Juice Method

Pour a small amount of pickle juice into a bowl and add a dirty penny. Let the penny soak for a few minutes before removing it, rinsing it, and setting it aside to dry.

The Lemon/Lime Juice Method

Squeeze some fresh lemon or lime juice into a small bowl and add a dirty penny. Let the penny bathe in the zesty juice for a few minutes and then remove it, rinse it, and set it aside to dry. Substitute bottled lemon or lime juice if necessary.

The Eraser Method

Use a pencil eraser to erase the grime and gunk from a dirty penny. Put some muscle into it. Rinse with water and set aside to dry.

Ask A Question And Seek An Answer

Start your penny cleaning experimentation with a question and then experiment to find an answer. For example, “Which of the five methods is the fastest way to clean a penny?”, “Which of the five methods requires the most physical labor?”, or “Which of the five methods is the messiest way to clean a penny?”

Instead of asking questions involving all five methods, you may want to focus on one method. For example, “Is a penny cleaner after three minutes soaking in pickle juice or is it cleaner after 10 minutes?”or “What’s the average time it takes to clean a penny with a eraser?”

Your experiments will, of course, vary depending on the question you ask.

Document Your Experiments

Keep track of your experiments by taking notes, creating charts, snapping photos, and shooting video. It not only helps you keep track of your experiments, it helps you show others what you’ve learned.


A few notes:

  • Use the five penny cleaning methods we share as starting points and see where they take you. For example, the pickle juice method may lead a child to ask, “Would a penny get clean if we put it inside a pickle?” Do the experiment!
  • Some kids get a taste for experimenting, so be ready to do more of it. Follow their lead and do your best to say yes to their experiment ideas. They may need you to be the voice of both reason and safety as well as scientific ethics. (“No, Kimberly, we can’t paste wings on the cat and see if she will fly, and here’s why….”)
  • Let the kids lead as much as possible. The more control they have over measuring, pouring, timing, and stirring the more they will learn and enjoy the process.
  • We realize that pennies are going extinct in some places as countries like Canada and Australia take them out of circulation and the world grows ever more digital, so you may have to explain to children exactly what pennies are.
  • Pennies are small. Don’t put them in your mouth or any other bodily opening. Make sure the children you try these penny cleaning experiments with do the same.


Learning about science and other STEM topics should be hands-on and active experiences with a focus on the process. Remember, kids learn by doing and they learn with their whole bodies. These experiments are a chance for them to engage all their senses in science.

If you have any questions or thoughts–or want to share the results of your experiments–we’d love to see them in the comments.

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I'm an early learning speaker, podcaster, content creator, author, and founder of Playvolution HQ and Explorations Early Learning.

After nearly 30 years working in early learning programs, Tasha now devotes her time to making Explorations Early Learning and Playvolution HQ work, quilting, and taking care of her pet duck, Tape.