Whether you have a very uncommon collection, some coins that can become valuable later, or just some spare change that has formed a strange film, you may be wondering how to clean rusty coins at home.
Let’s go over the best cleaning methods for both silver and copper coins and some cleaning don’ts.
- How to clean corroded coins
- Why do coins get corroded?
- How to prevent coins from corrosion
- What to avoid for cleaning coins at home
- More great metal cleaning articles
How to clean corroded coins
A Corrosion or rust happens when the metals in coins come into contact with air, chemicals, or even just the oils from our hands.
Some types of corrosion are permanent and will leave pits and scars on the surface of the coins. Other types of corrosion just affect the surface of the coins and can be easily cleaned.
Cleaning collectible coins can be more of a tricky process than ordinary coins. Most coin collectors actually discourage cleaning special coins, because it may do more harm than good. If you have a collectible coin, speak to a collector or expert before trying to clean it at home.
If you are thinking about bringing some potentially valuable coins to a collector, do not clean them beforehand.
One important thing to remember when cleaning any type of coin is not to soak the coin. Do not put it in any kind of liquid, and just leave it there! That can cause a damage that can not be repaired to the coin’s surface.
If you have a gold coin, use the Do It Yourself (DIY) method listed below to clean your gold coin.
How to clean corroded silver coins
Silver coins, especially older silver coins, can easily corrode and tarnish.
Tarnishing happens when silver comes is exposed to oxygen for a long period of time. Toning is a natural way and should not be removed from collectible coins.
Silver Coin experts have a safe – and easy! – method of cleaning silver coins:
- Prepare: Make sure your hands are clean, and you have a clean working surface. Find some soft towels, distilled water, a mild soap (such as Dawn or mild dish soap), and two plastic containers.
- Water: Prepare some soapy water in one of your plastic containers. Just a small portion of the soap will be enough. Mix it with the distilled water. In the second container, pour some clean distilled water.
- Clean: Sink the coin in the soapy solution. Use a soft-bristled toothbrush, a soft towel, or just use your fingers and gently rub the coin from the inside out.
- Rinse: Rinse the clean coin in the second container. If you need to use hot water, do so before rinsing it in the pure distilled water. You want a final rinse in distilled water.
- Dry: Lightly dry the coin with the towel. Leave it to air dry on the towel completely. Do not stack it with other coins. Gently pat – do not rub the coins dry.
How to clean green corroded copper coins
Copper will turn a green, yellow, or even black color when exposed to air. This can happen very quickly, too, not just after a lot of time!
Usually, copper coins will turn brown before they eventually turn to green. After a long period of time, that greening (called patina) will at the end turn to blue.
Things that are made from copper, such as pennies, can easily be repaired after they have corroded. To clean copper coins:
- Mix ¼ cup vinegar with 1 teaspoon of salt in a bowl that is non-metallic. Mix until the salt is completely dissolved.
- Drop the pennies into the mixture for about 5 minutes.
- If needed, use a soft towel or soft-bristled brush to scrub the coin.
- Rinse the coin very well under warm water.
- Pat the coin dry.
If you suspect that your copper coin may be valuable, use the cleaning method described above in the silver coin section.
DIY method of cleaning coins at home
A popular and simple method of cleaning coins at home involves using baking soda!
Here is a simple and easy way of cleaning regular corroded coins at home:
- Thoroughly wet and clean the coin with clean water – do not completely dump then in water. Use a fine-bristle toothbrush to lightly scrub off dirt or debris as necessary.
- Roll the wet coin in baking soda.
- Using the toothbrush from before, scrub the corrosion away. Scrub in circular motions to break up the built-up dirt.
- Rinse the coin – do not soak. Use a towel to make sure that all of the baking soda is removed.
- Repeat steps 1-4 until all the corrosion is gone.
- Dry the coin thoroughly – do not leave it wet.
Why do coins get corroded?
Silver coins will corrode mainly because silver coins are most times not 100% silver.
When pure silver is exposed to moisture, oxygen, oil, or other things that can pollute it, the silver will combine with sulfur, which will create the black silver sulfide film. Silver coins corrode due to the metals making up the coins reacting to the moisture, oil, and temperature from the hands that handle them.
Copper and gold corrode as the copper oxide within the coin react to oxygen. The corrosion process can start when the metal comes in contact with moisture, oils (such as from your hands), temperature, and even pollution from the environment.
Can you use corroded coins at checkout?
Some retailers will not take coins that are so corroded that the coins can not be recognized. However, most banks will still take corroded coins!
If your coins are corroded beyond recognition, use one of the cleaning methods listed above until the currency can be identified.
How to prevent coins from corrosion
The best way to prevent coins from corroding is to ensure you are handling and storing them correctly.
To handle your coin, make sure you only hold them by the third side, also known as the edge. If possible, handle rare coins using gloves.
When you are storing your coins, you want to ensure that they will be kept for as long as possible.
If you can, store them in a dark and enclosed box where air can not enter. If that is not possible, try to store them in an air-tight container, such as plastic Tupperware or some other kind of sealed container. Do not leave your coins out in the sun or in direct sunlight.
Store coins individually instead of dumping them into a big pile.
A very good coin collection storage method is using coin flips. Coin flips use vinyl, plastic, non-plastic, and saflips (or mylar) to hold the coin in a protective book or case. This ensures you can still view the coin, but it is not exposed to temperature, oil, or moisture.
If you are bringing your coins to a collector or dealer, do not separate a collection. If they are already in flips or a box, leave them there!
What to avoid for cleaning coins at home
While there are some tips on the internet for cleaning your coins at home – these methods may actually cause more harm than good!
Things to not do while cleaning your coins at home are:
- Never use acid or an acidic cleaning product on your coins.
- Don’t use bleach on metal.
- Don’t use a stiff bristle or wire brush to clean.
- Lemon juice is often cited – don’t clean coins with acid.
- Do not use metal polish or polish your coins.
- Do not use oils or gels to preserve the coins, causing them to reduce in quality over time.
- Never clean very old or antique coins.