Vinegar is most effective for cleaning copper. Other coins are molded from different metals, so the solution may not work as well on them. If you don’t have any vinegar on hand, a 1:1 ratio of water to acetone will produce the same effect.
For best results, use a pure, potent type of vinegar, such as distilled white vinegar. Make sure you select a container that isn’t made of metal. The chemical reaction created by mixing salt and vinegar can also react with other types of metals, potentially causing rust, discoloration or mild corrosion. [3] X Research source
Any variety of salt will do. It’s the chemical element that’s important, not the grains themselves. Vinegar alone is not strong enough to remove the worst buildup from old pennies. [5] X Research source
If you’re attempting to clean a large amount of pennies, you may need to empty the dish and mix up some fresh solution periodically.
Shake the pennies at the bottom of the dish as they soak to release even more buildup. Especially dirty coins can be left to soak for up to five minutes. [8] X Research source
Go over the entire surface of the coin using smooth, circular motions. You can also lightly scour the pennies using a toothbrush or cotton swab for a more thorough cleaning.
Once you’ve rinsed the pennies, set them aside on a layer of paper towels to dry. You may not be able to erase every last trace of discoloration on very old pennies. Eventually, other substances can set up in the metal, making them more or less permanent.
This can be especially damaging for pennies that already have a significant amount of scratching and wear.
A quick wash will also help neutralize the overpowering odor of the vinegar.
It’s okay to let the coins air dry, as long as there’s no standing water on them.
You might also use a small drawstring bag or jar, or carry it with you in a change purse. Placing your coins in a lidded container will defend them from deterioration-causing germs and moisture.
