Clean Coins How To

Clean Coins: Your Essential How-To Guide

Do you have dirty coins lying around? Perhaps you found an old coin or your everyday change looks dull. Knowing how to clean coins correctly makes a difference. Cleaning coins can bring back their shine, but doing it wrong damages their value. This guide will show you safe ways to clean various types of coins. We will cover important steps like assessing a coin’s value, understanding different cleaning methods, and focusing on preservation.

Takeaway

Assess Coin Value: Before cleaning, always determine if a coin has numismatic value. Consult experts or resources.
Choose Gentle Methods: For most coins, warm water and mild soap are best. Avoid harsh chemicals or abrasive tools.
Understand Metal Types: Different metals react differently to cleaning agents. Tailor your approach based on the coin’s composition.
Prioritize Preservation: Focus on removing surface dirt, not creating a “new” coin. Proper storage prevents future damage.

Clear, Concise Answer to Main Query

To clean coins, start by determining their value. For common coins, use warm water and mild soap, then gently rub with a soft cloth. For valuable or old coins, avoid aggressive cleaning to prevent damage that lowers their worth.

Why You Should or Should Not Clean Coins

Cleaning coins sounds simple. However, it is a complex topic for collectors. Many valuable coins lose worth when cleaned improperly. The dirt and patina on old coins are often part of their history. This natural aging shows authenticity and character. Collectors call this patina “toning.” Toning can actually increase a coin’s appeal and value. Removing it is a permanent change. It signals artificial alteration.

You should clean common circulation coins. These coins do not hold significant numismatic value. They may carry germs and dirt from daily use. A quick clean makes them look better. It also makes them safer to handle. Understanding this distinction is key. You avoid damaging rare pieces. You also enjoy the freshness of your everyday currency.

We often find old coins in unexpected places. These can be in the ground or in old family collections. They accumulate a lot of grime. This grime hides their true appearance. It also prevents proper identification. Sometimes, gentle cleaning is necessary just to identify the coin. This is different from making it shiny. You remove obstructing dirt, not natural aging. Always prioritize preservation over drastic changes.

Assessing Coin Value Before Cleaning

Before you clean any coin, you must assess its value. This step is critical. Many people have ruined valuable coins by cleaning them incorrectly. A coin’s value comes from its rarity, condition, and historical significance. Cleaning can erase evidence of its original state. This directly impacts its market appeal. Dealers and collectors prefer coins with original surfaces. They see cleaning marks as damage.

You can check a coin’s value in several ways. First, look for its mint mark, date, and denomination. Use reputable coin guides or online databases. Websites like PCGS or NGC offer extensive resources. These resources help identify specific varieties and their typical values. They often provide grading standards too. Next, consider consulting a professional numismatist. These experts assess coins for a living. They offer accurate valuations. They also advise on preservation. Never assume a coin is worthless without proper research.

Even if a coin seems dirty, do not rush to clean it. Dirt can protect the coin’s surface. It can hide minor flaws. Removing this layer often exposes scratches or corrosion. These imperfections were previously unseen. This exposure reduces the coin’s grade. A lower grade means less value. Learn how to clean coins for grading if you plan to submit them. However, for most valuable coins, the answer is often “do not clean.”

Essential Tools and Safe Cleaning Agents

Choosing the right tools and agents is vital for coin cleaning. Improper materials can scratch or pit coin surfaces. This damage is irreversible. Always opt for the gentlest options first. You want to preserve the coin’s integrity. Start with simple household items. These are often sufficient for common dirt. Avoid anything abrasive. Abrasive materials include harsh brushes or scouring pads.

Basic Cleaning Kit

Distilled Water: Tap water contains minerals and chlorine. These can leave residues or react with coin metals. Distilled water is pure. It rinses coins without adding new contaminants. Use it for soaking and final rinses.
Mild Soap: A non-abrasive, pH-neutral soap is ideal. Dish soap like Dawn works well. Avoid soaps with strong detergents or added moisturizers. These can leave a film. Mix a small amount with distilled water.
Soft Cotton Cloths: Microfiber cloths are good too. They are lint-free. They absorb water efficiently. Use them for gentle drying. Do not rub vigorously. Pat the coin dry.
Soft Bristle Brush: A camel hair brush or a very soft toothbrush can remove loose dirt. Use it with extreme caution. Brush lightly, only on heavily soiled areas. I always test on a common coin first.

Safe Cleaning Agents for Specific Coin Types

Different coin metals react to different agents. Silver coins often tarnish. Copper coins develop green patina. Knowing the metal helps choose a specific, gentle solution. For example, how to clean silver coins involves different considerations than copper or bronze.

Olive Oil: This is a safe option for copper and bronze coins. It slowly loosens dirt. It does not strip patina. Soak coins in olive oil for days or weeks. This method is slow but gentle. It protects the coin’s surface.
Acetone (Pure): Pure acetone (like nail polish remover without added ingredients) removes organic residues. It is safe for most metals. It evaporates completely. It does not leave a film. Use it in a well-ventilated area. Avoid plastic containers.
Baking Soda Paste (Very Gentle): A paste of baking soda and water can gently polish some common coins. Use sparingly. Rub very lightly. Rinse thoroughly. This is usually for common, non-valuable coins.
Hydrogen Peroxide (Careful Use): How to clean coins with hydrogen peroxide can remove some organic grime. It can be aggressive on some metals. Test it on a common coin first. Use it for short periods.

Always remember: Less is more when cleaning coins. The goal is preservation, not perfection.

Step-by-Step Coin Cleaning Techniques

Cleaning coins requires a gentle hand and patience. Rushing the process leads to damage. Always work in a clean area. Use a soft mat to prevent scratches if a coin drops. Remember, these methods are mainly for common, non-valuable coins.

Method 1: Warm Water and Soap Soak (General Purpose)

This is the safest and most recommended method for most circulation coins. It removes general dirt and grime. I start with this for any coin I intend to clean.

Prepare a Solution: Get a bowl of warm, distilled water. Add a few drops of mild, pH-neutral dish soap. Mix it gently.
Soak the Coins: Place your coins into the soapy water. Let them soak for 15-30 minutes. For heavily soiled coins, you can soak them longer, even overnight. This softens the dirt.
Gentle Agitation: After soaking, gently swirl the coins in the water. You can also use your fingers to rub them very lightly. Do not use your fingernails. Avoid rubbing coins together.
Soft Bristle Brush (Optional): If some dirt remains, use a very soft-bristle brush. Gently brush the coin under running distilled water. Brush only visible dirt.
Rinse Thoroughly: Rinse each coin under a stream of cool, distilled water. Ensure all soap residue is gone. Soap residue causes future discoloration.
Dry Carefully: Place coins on a soft, lint-free cloth. Pat them dry gently. Do not rub. You can also let them air dry completely on a clean cloth. Ensure they are fully dry before storage. Moisture causes corrosion.

This method works well for everyday coins. It removes surface grime without harsh chemicals.

Method 2: Olive Oil Soak (For Copper and Bronze Coins)

Olive oil is excellent for older copper and bronze coins, especially those found in the ground. It is very gentle. It can take a long time, but it protects the coin’s original surface. This method is often used for how to clean bronze coins or ancient finds.

Preparation: Place your copper or bronze coin in a small, non-reactive container. A glass jar works well.
Submerge in Olive Oil: Pour pure olive oil over the coin. Make sure it is completely submerged.
Long-Term Soaking: Let the coin soak for several weeks or even months. Check it periodically. The oil slowly loosens dirt and corrosion.
Gentle Removal: After soaking, carefully remove the coin. Gently rub it with your fingers or a soft cloth. The loosened dirt should come off easily. Do not force anything.
Rinse and Dry: Rinse the coin with warm, distilled water. Then, pat it dry with a soft cloth.

This method is slow but preserves the coin’s historical patina. It is excellent for how to clean old coins found in the ground.

Method 3: Acetone Dip (For Organic Residues)

Pure acetone effectively removes organic residues like glue, tape, or PVC residue. It evaporates cleanly. It does not react with most metals. Make sure you use 100% pure acetone. Check the label carefully.

Safety First: Work in a well-ventilated area. Acetone fumes are strong. Wear gloves.
Dip the Coin: Hold the coin by its edges or use plastic-tipped tweezers. Dip it into a small glass container of pure acetone.
Soak Briefly: Let the coin soak for a few minutes. For tougher residues, you can soak longer.
Rinse and Dry: Remove the coin. Let the acetone evaporate completely. You can rinse it quickly with distilled water afterward. Then, pat dry.

This method is useful for targeted cleaning of specific contaminants. It is crucial to use only pure acetone.

Specific Coin Cleaning Challenges

Some coins present unique cleaning challenges. Rust, corrosion, and severe tarnish need special attention. Addressing these issues safely requires understanding the coin’s metal. Improper methods can cause irreparable damage. My experience has taught me patience here.

Removing Rust from Coins

Rust primarily affects iron or steel coins. Many older coins, particularly European ones, contain iron. Rust is iron oxide. It eats into the metal. Removing rust without damaging the coin is difficult. Strong rust removers are highly aggressive. They can pit the coin’s surface. This lowers its grade and value.

Gentle Approach: For light rust, consider an olive oil soak. This method is slow but safe. It gradually loosens the rust.
Electrolysis (Advanced): This method uses electricity to reverse the rusting process. It is effective but risky. It requires specialized equipment. It can also over-clean the coin. This may result in an unnatural appearance. This is usually for very common, heavily rusted coins.
Vinegar Soak (Very Cautious): Diluted white vinegar can dissolve rust. However, it is acidic. It can damage a coin’s surface quickly. Use for very short dips (seconds). Rinse immediately and thoroughly with distilled water. Only use this on common coins. Learn more about how to clean rusty coins.

I only use electrolysis on common “junk” coins. I do not recommend it for anything with potential value.

Dealing with Corroded Coins

Corrosion is broader than rust. It is a chemical reaction between metal and its environment. It appears as green or blue patches on copper or bronze. Silver coins can show black tarnish. How to clean corroded coins depends on the metal and corrosion type.

For Copper/Bronze Corrosion: The olive oil soak is your best bet. It slowly works on the corrosion. It helps lift it away. For stubborn patches, gentle scraping with a wooden toothpick might help after soaking. Do not use metal tools.
For Silver Tarnish: Silver tarnish is silver sulfide. A baking soda paste (very thin, very gentle application) can reduce it. Some people use an aluminum foil and baking soda bath with hot water. This creates an electrochemical reaction. It reverses the tarnish. This method can strip all toning. This means it can reduce a coin’s value. Use with extreme caution on common silver. Do not use on collectible silver coins.
For Nickel Coins: Nickel coins are durable. They typically clean well with warm water and mild soap. For persistent dirt, a short soak in rubbing alcohol can help. Check out tips on how to clean nickel coins.

Avoid strong acids or bases. These chemicals aggressively strip the coin’s surface. They can leave it pitted or unnaturally bright. This damage is irreversible.

When Not to Clean Coins: Collector’s Golden Rule

The most important rule in coin collecting is often: Do not clean your coins. This applies especially to rare, valuable, or old coins. Cleaning them nearly always reduces their value. This fact surprises many new collectors. They believe a shiny coin is a good coin. Professional collectors and graders think differently.

Coins acquire a natural patina over time. This patina is a thin layer of oxidation. It forms on the coin’s surface. This layer protects the metal. It also provides a unique aesthetic appeal. For numismatists, this original toning indicates authenticity. It shows the coin has been undisturbed. Removing this patina leaves the coin looking unnatural. It can also expose microscopic scratches. These scratches were previously hidden. These marks are called “hairlines.” They are a sign of improper cleaning.

Grading services like PCGS and NGC penalize cleaned coins heavily. A cleaned coin receives a “cleaned” designation. This drastically reduces its market value. A coin worth thousands of dollars uncleaned might be worth only tens after cleaning. The monetary loss is significant. I always tell new collectors to research before acting.

If you find an old coin, resist the urge to clean it. Instead, protect it. Place it in a non-PVC coin holder. Then, show it to a professional coin dealer or grader. They can assess its true condition and value. They will advise you on preservation. Often, the best way to “clean” a valuable coin is not to touch it at all. This simple act preserves its historical integrity and financial worth.

Specialized Cleaning Methods and Considerations

While gentle methods are generally best, some specialized situations call for different approaches. These are often for specific coin types or severe conditions. Always proceed with extreme caution. My advice is to practice on common, valueless coins first.

Cleaning Roman Coins and Ancient Artifacts

Ancient coins, like how to clean Roman coins, require unique care. They are often made of bronze, copper, or silver. They have spent centuries buried. They carry heavy encrustations. Aggressive cleaning destroys their historical context.

Soaking in Distilled Water: A prolonged soak in distilled water is the safest first step. Change the water daily. This gradually softens the dirt.
Dental Tools/Wooden Picks: After soaking, use non-abrasive tools. Wooden toothpicks or plastic dental tools can gently pick away softened dirt. Work slowly. Be patient. This is a very time-consuming process.
Olive Oil: As discussed, olive oil is excellent for bronze and copper ancient coins. It can take months, but it preserves the patina.

Never use harsh chemicals on ancient coins. They can dissolve the very metal of the coin. The goal is conservation, not restoration to a “new” state. You want to reveal details, not strip the coin bare.

Ultrasonic Cleaning for Coins

Ultrasonic cleaners use sound waves to create microscopic bubbles. These bubbles agitate liquid. This action dislodges dirt from surfaces. They are popular for jewelry. For coins, they are controversial.

Pros: They can remove dirt from intricate areas. They do not involve rubbing.
Cons: They can cause micro-abrasions on soft metals. They can also dislodge existing patina. Some argue the vibrations can be harmful. They might damage the coin’s molecular structure over time.
Recommendation: Use with caution on common, non-valuable coins only. Use pure distilled water. Avoid detergents. Do not use for valuable or collectible coins. This method is generally frowned upon by serious numismatists.

Bleach and Other Harsh Chemicals: A Warning

I strongly advise against using bleach or other harsh chemicals. Products like how to clean coins with bleach often appear in online searches. Bleach contains chlorine. Chlorine is highly reactive. It will aggressively attack coin metals. It can permanently etch or pit a coin’s surface. This leaves a dull, unnatural finish. The damage is irreversible.

Consequences: Bleach ruins the coin’s original luster. It also creates a distinct, artificial appearance. Professional graders can easily spot bleach damage. This renders the coin worthless to collectors.
Other Harsh Chemicals: Acids (like strong vinegars, lemon juice concentrate) and abrasive cleaners (like Comet) also cause irreversible damage. They remove metal from the coin. This thins it out. It destroys surface details.

Always err on the side of caution. If a coin is valuable, do not clean it. If it is common, use only the gentlest methods.

Preserving Cleaned Coins and Proper Storage

After cleaning your coins, proper preservation is crucial. Improper storage can lead to re-tarnishing, corrosion, or physical damage. The goal is to protect your coins from environmental factors. This includes moisture, air pollutants, and physical abrasion. I have seen many good coins ruined by poor storage.

Air-Tight Storage

Air is a coin’s enemy. It contains oxygen and pollutants that cause tarnishing and corrosion.

Flips: Use Mylar or polyester flips. These are inert. They do not react with coin metals. Avoid soft PVC (polyvinyl chloride) flips. PVC releases plasticizers. These chemicals leach onto coins. They cause a sticky, green residue. This residue is called “PVC damage.” It is extremely hard to remove.
Slabs: Professional grading services encapsulate coins in hard, sealed plastic holders. These “slabs” are air-tight. They offer the best protection. They also protect the coin from handling.
Coin Tubes: For rolls of common coins, plastic coin tubes are effective. Ensure they are made of inert plastic, like polyethylene or polypropylene.

Always handle coins by their edges. Your skin contains oils and acids. These can leave fingerprints. Fingerprints can etch onto a coin’s surface over time. This creates permanent marks.

Temperature and Humidity Control

Environmental conditions play a big role in coin preservation.

Stable Temperature: Store coins in a location with a stable temperature. Extreme temperature swings cause metal expansion and contraction. This can lead to cracks or surface damage.
Low Humidity: High humidity is a major cause of corrosion. It promotes chemical reactions on the coin’s surface. Store coins in a dry environment. Desiccants like silica gel packets can help control humidity in enclosed spaces. Change them periodically.
Away from Fumes: Keep coins away from sources of chemical fumes. This includes cleaning supplies, fresh paint, or even certain types of wood. These fumes can accelerate tarnishing.

Regular Inspection

Even with good storage, check your coins periodically.

Look for Changes: Inspect for new spots, haze, or discoloration. Catching these problems early can prevent further damage.
Rotate Display: If you display coins, rotate them occasionally. This exposes different sides to light and air. This prevents uneven toning.

Proper storage is the final step in how to clean coins DIY and keep them pristine. It ensures your efforts last.

Conclusion

Cleaning coins can be a rewarding task, but it requires careful consideration. Remember that for valuable or rare coins, the best approach is often no cleaning at all. Preserving their original state, including any natural patina, maintains their numismatic value. For everyday currency or coins found in the ground that lack significant value, gentle cleaning methods are your safest bet.

Always start with the least invasive methods, such as warm distilled water and mild soap. Understand the specific metal composition of your coin, as different metals react uniquely to cleaning agents. Avoid harsh chemicals like bleach or abrasive tools, as these cause irreversible damage and significantly reduce a coin’s appeal to collectors. Your objective is to gently remove surface grime, not to make the coin look brand new. After cleaning, proper storage in inert, air-tight containers in a stable environment is essential to protect your efforts. By following these guidelines, you can responsibly care for your coins and ensure their preservation for years to come.