Have you ever reached into your pocket or purse and pulled out some pennies only to find they’ve turned green? You’re not alone – this is a common problem many of us encounter with pennies after they’ve been in circulation for a while.

If you want to restore the original copper color of your pennies, cleaning them is easy to do at home with some simple household ingredients. In this comprehensive guide, we’ll walk you through an effective method for cleaning green pennies in just a few steps.

If you’re short on time, here’s a quick answer to your question: Soak the green pennies in a bowl with 1 part vinegar and 1 part salt for 5-10 minutes. This acidic solution will help lift the green patina that builds up on pennies over time.

Scrub with an old toothbrush and rinse clean for shiny pennies again.

In this 3000 word guide, we will cover everything you need to know about cleaning pennies step-by-step, from understanding why they turn green in the first place to testing different methods and ingredients to remove the patina.

We’ll also provide tips on how to store your cleaned pennies properly to prevent them from turning green again.

What Causes Pennies to Turn Green?

Have you ever wondered why your pennies sometimes develop a greenish tint over time? The discoloration is actually a result of a natural oxidation process that occurs when the copper in the penny reacts with the elements in its environment.

Additionally, there are certain environmental factors that can speed up this tarnishing process. Let’s take a closer look at these causes.

The Natural Oxidation Process of Copper

Copper is a metal that is highly reactive with oxygen. When a penny is exposed to air, the copper atoms on its surface react with oxygen molecules to form copper oxide. This reaction is known as oxidation.

Over time, the copper oxide layer can continue to react with air and moisture, leading to the formation of other compounds such as copper hydroxide and copper carbonate. These compounds contribute to the greenish color that we often associate with tarnished pennies.

It’s important to note that this oxidation process is a natural occurrence and happens to all copper-based materials, not just pennies. The rate at which a penny tarnishes can vary depending on various factors such as the amount of exposure to air and moisture, temperature, and the presence of other chemicals in the environment.

Environmental Factors That Contribute to Tarnishing

While the natural oxidation process plays a significant role in the green discoloration of pennies, certain environmental factors can accelerate the tarnishing process. Here are some common culprits:

  • Air pollutants: Pollutants in the air, such as sulfur compounds, can react with the copper surface and speed up the oxidation process.
  • Moisture: High humidity levels can increase the rate of oxidation, especially when combined with air pollutants.
  • Acidic substances: Exposure to acidic substances, such as vinegar or lemon juice, can cause the copper oxide layer to dissolve, leading to faster tarnishing.

It’s worth mentioning that cleaning green pennies can be a fun and educational activity. There are several methods you can try, but it’s important to be cautious and avoid using harsh chemicals that could damage the penny’s surface.

If you’re unsure about the best cleaning method, consider consulting a professional or referring to reputable sources like the United States Mint website.

How to Clean Green Pennies

If you have a collection of old pennies that have turned green over time, you may be wondering how to restore them to their original shine. Cleaning green pennies can be a fun and rewarding activity, and with the right supplies and techniques, you can easily bring back their luster.

In this step-by-step guide, we will walk you through the process of cleaning green pennies and restoring them to their former glory.

Supplies You Will Need

Before you begin cleaning your green pennies, gather the following supplies:

  • Vinegar
  • Salt
  • Other household acids (optional)
  • A small container or bowl
  • A toothbrush
  • Water
  • A soft cloth or paper towel

Having these supplies on hand will make the cleaning process much easier and more effective.

Making a Vinegar and Salt Solution

One of the most common methods for cleaning green pennies is by using a vinegar and salt solution. To make this solution, follow these steps:

  1. Fill a small container or bowl with vinegar.
  2. Add a tablespoon of salt to the vinegar and stir until the salt is dissolved.

The vinegar and salt solution creates a chemical reaction that helps remove the green tarnish from the pennies. This method is safe and effective for most pennies, but it’s always a good idea to test it on a small area first.

Using Other Household Acids

If the vinegar and salt solution doesn’t fully clean your green pennies, you can try using other household acids. Lemon juice, ketchup, or even Coca-Cola can be effective in removing tarnish from pennies.

Simply soak the pennies in the chosen acid for a few minutes, then rinse them with water and pat them dry.

Soaking the Pennies

Once you have your vinegar and salt solution or other household acid ready, you can begin cleaning your green pennies. Start by placing the pennies in the solution and letting them soak for a few minutes. The solution will work to dissolve the green tarnish, making it easier to remove.

Scrubbing with a Toothbrush

After the pennies have soaked, take a toothbrush and gently scrub each penny. The bristles of the toothbrush will help remove any remaining tarnish and dirt. Be careful not to scrub too hard, as this could damage the pennies.

Rinsing and Drying

Once you have finished scrubbing the pennies, rinse them thoroughly with water to remove any residue from the cleaning solution. After rinsing, pat the pennies dry with a soft cloth or paper towel. Avoid rubbing the pennies too hard, as this could cause scratches.

And there you have it! Your green pennies should now be clean and shiny, ready to be admired or added back to your collection. Remember to handle your pennies with care and avoid using harsh chemicals or abrasive materials that could potentially damage them.

Tips for Storing Cleaned Pennies

Once you have successfully cleaned your pennies and restored their shine, it’s important to store them properly to maintain their condition. Here are some helpful tips for storing your cleaned pennies:

Keep Pennies in an Air-Tight Container

One of the most important factors in preserving the cleanliness of your pennies is to keep them in an air-tight container. Exposure to air can cause oxidation and tarnishing, which can reverse the cleaning process. Choose a container that seals tightly to prevent any air from getting in.

A small plastic bag or airtight coin capsule can work well for this purpose.

Use Silica Gel Packets

Silica gel packets can be incredibly useful for storing cleaned pennies. These small packets are commonly found in shoeboxes, electronics packaging, and some food products. They are designed to absorb moisture and help keep the surrounding environment dry.

Place a few silica gel packets in your container along with the cleaned pennies to help absorb any moisture that may be present. This will help prevent any potential damage caused by humidity.

Store in Coin Collecting Folders or Books

If you’re an avid coin collector, you may already have coin collecting folders or books. These specialized storage solutions are designed to hold and protect coins, including pennies. They typically have individual slots or pockets for each coin, allowing you to organize and display your collection.

Storing your cleaned pennies in these folders or books not only keeps them safe from damage but also makes it easier to showcase your collection to others.

Remember, proper storage is essential for maintaining the cleanliness and value of your cleaned pennies. By following these tips, you can ensure that your pennies remain in great condition for years to come.

Frequently Asked Questions

How Long Does It Take to Clean Pennies?

The time it takes to clean pennies can vary depending on the method you choose. One popular method is using vinegar and salt. This process typically takes around 10-15 minutes. However, if you prefer a quicker method, you can also use lemon juice or ketchup, which can clean pennies in just a few minutes.

Ultimately, the choice is yours based on the time you have available and the level of cleaning you desire.

Will Cleaning Pennies Decrease Their Value?

Cleaning pennies generally does not decrease their value, especially if you use methods that are gentle and non-abrasive. In fact, cleaning green pennies can often enhance their appearance and make them more appealing to collectors.

However, it’s important to note that altering the surface of a rare or valuable penny may decrease its numismatic value. If you have valuable coins, it’s best to consult with a professional coin dealer or collector before attempting to clean them.

Can I Use Other Ingredients Besides Vinegar?

Absolutely! While vinegar is a popular choice for cleaning green pennies, there are other household ingredients that can be just as effective. Lemon juice, for example, contains citric acid that can help dissolve the green oxidation on pennies.

Ketchup is another surprising option, as its acidity can also help remove tarnish. You can even try using a mild abrasive like baking soda mixed with water to create a paste. Experimenting with different ingredients can be fun and may yield different results, so feel free to get creative!

What Is the Green Substance on Pennies?

The green substance on pennies is called copper oxide. It forms when copper reacts with oxygen in the air, resulting in a greenish patina. This patina is a natural process of oxidation that occurs over time.

While some collectors appreciate the aged look, others prefer to restore the pennies to their original shine. Removing the green substance can reveal the beautiful copper color underneath and make the pennies look like new again.


In conclusion, with just a few simple household ingredients and supplies, you can easily clean green pennies and restore them to their original bright copper finish. While pennies naturally oxidize and tarnish from circulation over time, this oxidation can be reversed through an acidic bath.

Just remember to handle your restored pennies carefully and store them properly to prevent re-tarnishing.

We hope this comprehensive guide gave you all the tips, tricks, and knowledge you need to clean all the green pennies you come across. Understanding what causes the oxidation and how to remove it will save your pennies from the trash.

With a little time and elbow grease, your pennies will soon be shiny and bright once again.

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