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Polishing Pennies

Sweet Pea is 4 years old.

From: This idea was from Quirky Momma.


  • 1/4 cup Vinegar.
  • 1 tsp Salt.
  • A small (non-metal) bowl for the vinegar and salt.
  • A bowl of water.
  • Several grubby pennies.
  • Rags for scrubbing the pennies.
  • Towels for containing the mess.


  • Mix the salt and vinegar in the glass bowl.
  • Put a towel in front of your tot and put a tarnished penny on it.
  • Show your tot how to dip the edge of a rag in the salt and vinegar mixture.
  • Rub the penny with the wet rag on both sides  for 15 or 20 seconds until it is shiny.

  • Drop the penny in the water to rinse it and then dry it off.
  • Allow your tot to clean the rest of the pennies.

Observations: Sweet Pea is borderline obsessed with cleaning things, so this was a huge hit.  This activity provides instant gratification because the pennies start to shine up immediately when they come in contact with the vinegar and salt solution

At first, Sweet Pea stuck with cleaning one penny at a time, but we soon moved to dunking several at once into the cleaning liquid.

This activity was a lot of fun for both of us and I would recommend it for kids of all ages.

An Accidental Science Lesson

When we started this activity, I didn’t include the salt because I assumed it was just there to provide grit for scrubbing.  I was very surprised when the vinegar alone didn’t shine up the pennies at all!   However, as soon as I added salt to the vinegar, the  “dirt” magically disappeared, so I figured there must be a chemical reaction occurring.  Google to the rescue!  I found the following explanation at along with 2 related experiments.

The “dirt”  or tarnish on a penny is actually copper oxide which forms when the copper on the penny reacts with oxygen in the air.   When you mix the vinegar and salt it creates an acid which is able to remove the copper oxide from the outside of the pennies.  Afterwards some copper ions get left behind in the liquid.   You can then recover the copper by “electroplating” a nail.

I found 2 nails (one galvanized and one non-galvanized).  We put them both in the vinegar water and waited.  After about 10 minutes, we removed both nails and  saw that the non-galvanized nail had been copper-plated.  How cool is that?

Notes from the Trenches:  If you (or your child has a paper cut), dipping it in the vinegar will hurt like the dickens!  Yowch!

Rating: 3 Stars * (Fun, Easy, Frugal)


3 comments to Polishing Pennies

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