Do you have a jar full of sticky, dirty, or tarnished coins sitting on your dresser? Whether you found a wheat penny in the parking lot or just want your quarters to shine before spending them, knowing how to clean coins properly is essential.
However, scrubbing the wrong coin can wipe away hundreds of dollars in value instantly. We’re covering how to clean coins safely at home without ruining your collection.
Key Takeaways
- Never clean rare or collectible coins: Cleaning removes the “patina” and significantly lowers the numismatic value.
- Use the safest method first: Warm distilled water and mild dish soap is the only cleaning method recommended for potentially valuable coins.
- Avoid abrasives: Toothpaste, baking soda, and wire brushes will scratch the metal surface permanently.
- Store correctly: Keep coins in acid-free holders and control humidity to prevent future oxidation.
The Golden Rule: Should You Clean Your Coins?
Before you grab a toothbrush, stop and inspect your coins. If you possess a coin that is old, rare, or collectible (numismatic), do not clean it.
Collectors prize the “patina” on a coin. This is the natural toning that occurs over time as the metal reacts with the atmosphere. Stripping this layer makes the coin look unnaturally bright and reveals microscopic scratches. A skilled appraiser can spot a cleaned coin instantly, and it can reduce the value by 50 percent or more.
If you have a potentially valuable coin, consult a professional. If you are cleaning common “pocket change” or “junk silver” that has no collectible premium, you can use the methods below.
The Safest Method: Soap and Water
This is the only method you should consider for coins that might have some value. It removes surface dirt and grease without stripping the metal or causing chemical reactions.
- Time: 15-20 minutes
- Difficulty: Beginner
What You’ll Need
- Mild dish soap
- Distilled water (tap water contains minerals that cause spots)
- A shallow plastic container
- A soft microfiber cloth
1. Create a Soapy Bath
Fill your plastic container with warm distilled water. Add a few drops of mild dish soap. Do not use lemon-scented soaps or those with harsh additives; basic liquid soap is best.
2. Soak the Coins
Place the coins individually into the water. Do not stack them, as they can scratch each other. Let them soak for 10 to 15 minutes to loosen the grime.
3. Rinse and Pat Dry
Remove the coins and rinse them thoroughly with fresh distilled water. Do not rub the coins dry. Rubbing causes friction scratches. Instead, lay them on a soft towel and gently pat them dry, or allow them to air dry completely before storing.
Methods for Common “Junk” Coins
If you are cleaning modern currency, foreign coins with no value, or metal detecting finds that are encrusted with dirt, you can use stronger household items. These methods are effective but slightly abrasive or acidic.
Vinegar (For Brightening)
Vinegar is acidic and attacks the oxidized layer on the coin.
- Place your coins in a small glass bowl.
- Pour white vinegar over the coins until submerged.
- Let them soak for 30 minutes (no longer, or the acid will pit the metal).
- Rinse thoroughly with water and dry.
Baking Soda (For Scrubbing)
Baking soda acts as a mild abrasive. This will leave micro-scratches, so only use this on coins you do not intend to sell to a collector.
- Mix baking soda and a small amount of water to form a paste.
- Apply the paste to the coin using your fingers.
- Gently rub the grime away.
- Rinse promptly to remove all residue.
Coca-Cola
The phosphoric acid in Coke eats away rust and tarnish.
- Fill a cup with Coca-Cola.
- Drop a single coin in (soaking multiple can cause contact marks).
- Wait 15 minutes. Check the coin.
- Rinse well to remove the sticky sugar residue.
Hydrogen Peroxide
This is good for sterilizing coins, which is helpful if you handle a lot of cash.
- Place coins in a bowl.
- Cover with hydrogen peroxide.
- Let them soak for 24 hours.
- Rinse and air dry.
How to Remove PVC Residue (Acetone)
If your coins have a sticky, green slime on them, this is likely PVC damage from storing them in cheap plastic flips for too long. Soap won’t fix this, but pure acetone will. Note that we are talking about 100% pure acetone from a hardware store, not nail polish remover.
1. Prepare the Solvent
In a well-ventilated area (acetone fumes are strong and flammable), pour a small amount of pure acetone into a glass container. Do not use plastic, as acetone melts plastic.
2. Short Soak
Dip the coin into the acetone for 5 to 10 seconds. The green goo should dissolve rapidly.
3. Rinse
Rinse the coin with distilled water immediately. Acetone evaporates quickly, but you want to ensure the dissolved plastic residue washes away rather than drying back onto the coin.
The “Long Soak” for Ancient Coins (Olive Oil)
This method is popular for ancient coins or metal detecting finds that are heavily encrusted with earth. It is a slow, gentle process.
1. Submerge in Oil
Place your coins in a jar and cover them with olive oil.
2. Wait
This is not a quick fix. You may need to leave the coins for several weeks or even months. The oil slowly penetrates the dirt and separates it from the metal.
3. Check and Change
Check the coins weekly. If the oil gets dirty, replace it. Once the dirt is loose, use a soft toothpick to gently flake it away, then wash with warm soapy water to degrease the coin.
Tips For Storing Coins Correctly
Once your coins are clean and dry, proper storage prevents them from oxidizing again.
- Use Acid-Free Holders: Look for Mylar flips or holders labeled “PVC-Free.” PVC releases acids over time that turn coins green.
- Control Humidity: Moisture is the enemy. Keep your collection in a room with low humidity, or add silica gel packets to your storage box.
- Avoid Temperature Swings: Do not store coins in attics or basements where temperatures fluctuate wildly.
- Handle by Edges: Oils from your fingers cause fingerprints that can eventually etch into the metal. Always hold coins by the rim.
FAQs
How Do Professionals Clean Coins?
Professionals rarely “clean” coins in the traditional sense. They “conserve” them. Conservation involves removing active contaminants (like PVC residue or verdigris) that are damaging the metal, without stripping the original surface or patina. They use specialized chemical solvents that do not react with the coin’s metal.
What is the Fastest Way to Clean Coins?
The fastest safe way is mild soap and water. If you don’t care about value and just want shiny change, an ultrasonic cleaner or a 15-minute soak in vinegar creates quick results, but these methods can lower the value of collectible items.
Can You Use Bleach to Clean Coins?
No. Never use bleach on coins. Bleach contains chlorides that cause a chemical reaction with copper, silver, and other metals. It will darken the coin, cause pitting, and ruin the surface permanently.
What Coins Are Worth a Lot of Money?
Rare dates, mint errors, and coins with high precious metal content (like pre-1964 US silver coins) are valuable. Examples include the 1909-S VDB Lincoln Penny or the 1916-D Mercury Dime. Always check a “Red Book” or online price guide before cleaning any older coin.
How Do You Tell a Coin Has Been Cleaned?
A cleaned coin often looks “too shiny” and flat, lacking the “cartwheel” luster of a mint-condition coin. Under magnification, you will see thousands of tiny hairlines (scratches) running in the same direction from scrubbing. The surface may also look washed out or unnatural compared to other coins of the same era.
How Much Does It Cost to Get Coins Graded?
Grading typically costs between $20 and $60 per coin, plus shipping and insurance fees. This requires a membership to services like PCGS or NGC. Because of the cost, you should generally only grade coins worth at least $150 to $200.
Is It Safe to Use Toothpaste on Silver Coins?
No, it is not recommended for valuable silver. Toothpaste contains silica, which is a mild abrasive. While it makes the silver shine, it does so by scratching off the top layer of metal. This leaves micro-abrasions that ruin the numismatic value of the coin.
In Coinclusion
If you just want to spruce up some quarters for a craft project, household items like vinegar or soapy water work wonders. However, if you stumble across an old silver dollar or a wheat penny, take a step back.
Preserving history is usually worth more than making it shiny. When in doubt, stick to distilled water, a gentle pat dry, and a call to your local coin shop.
