This post is about a penny-cleaning science experiment using kitchen staples. Did you know things like ketchup, salt, vinegar, and lemon juice will clean and brighten pennies? If your pennies are all bright and shiny, you can keep them in water overnight to allow them to darken for this experiment. Warning, children might like to do this over and over!

First, start with a dirty penny. These are highly available! If you have none, start a collection when you get change from shopping. We tried ketchup first.

Penny Cleaning Science Experiment Using Kitchen Staples

Then “wash” the penny with ketchup. This can be accomplished without touching the penny by putting it in a paper towel, folding the towel over, and then rubbing the two sides together over the penny. Using ketchup requires more elbow grease than some of the other options.


Then carefully observe with a magnifying lens. This can actually be done before and after cleaning the penny. clean-a-penny-with-ketchup

Penny Cleaning with Other Food Ingredients

Just be sure not to let the children mix the different cleaners together when penny cleaning. Things like salt might cause some pain to any tiny cuts they might have on their hands. This is a chance for them to wear gloves just like the doctors and nurses wear. At least have hand washing very accessible for them to rinse off salt or vinegar that may sting their skin. They should be supervised to prevent them from deciding to try household cleaners and other items that children should not use. The work page shows the ingredients that may safely be combined. Click on this link for an instant download of the science work along PDF here:

shine-a-penny-experiment PDF


We tried placing fruit slices on pennies for awhile and returning in about an hour. The lime slice worked the best with this method. We did not have to rub the lime juice. Actually, just leaving a penny in one of the proven methods to clean it will work if some time can be allowed.


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You might also like our dancing dime experiment and video, as well.


Thank you for reading! Carolyn