Polish some dirty pennies with only a pencil.
Always remember to wear eye protection during science experiments. Never handle sharp objects, open flames, chemicals, or other dangerous objects without adult permission and supervision.
Out of your pennies, try to find the dirtiest, ugliest, greenest one. We had a few fitting this description in our piggy bank...
For your first attempt to shine up a penny, take a small piece of paper towel and dampen it slightly with water.
With as much effort as you can, try for a few seconds to polish the penny with the paper towel. You'll probably find that not much is happening. This is because the green coating on your pennies isn't just on the surface, but is actually part of the penny itself. To remove this layer, we're going to have to use something abrasive to scratch off this microscopic layer and polish the penny.
Now, take the pencil's eraser and try to "erase" the patina covering the penny. This time, if you put a bit of effort into it, you might see your penny slowly starting to become shinier.