Cleaning a brass coin can be a straightforward process using common household items. It is crucial, however, to proceed with caution to prevent damage to the coin’s surface or any potential collector value. This guide provides a comprehensive overview of how to clean a brass coin, detailing various methods and important considerations to ensure its preservation.
Understanding Brass Coins and the Importance of Careful Cleaning
Brass is an alloy primarily composed of copper and zinc, known for its golden appearance and resistance to corrosion. Over time, brass coins can accumulate dirt, grime, and tarnish, which is a thin layer of corrosion that forms on the surface. While cleaning can restore a coin’s luster, improper methods can cause irreversible damage. The goal when cleaning a brass coin is to remove unwanted surface contaminants without altering the coin’s original state or removing its patina.
What is Patina?
Patina is a natural layer that forms on the surface of brass (and other metals) due to oxidation over time. It often appears as a brownish, greenish, or even blackish film. For many collectors, patina is a desirable feature, indicating the coin’s age and authenticity. Removing a natural patina can significantly decrease a collectible coin’s value and expose the bare metal to further, potentially more aggressive, corrosion. Therefore, knowing when not to clean a brass coin is as important as knowing how to clean a brass coin.
When to Avoid Cleaning a Brass Coin
Before attempting any cleaning, consider these critical points:
- Valuable or Collectible Coins: If a brass coin is rare, old, or has potential historical or numismatic value, do not clean it. Cleaning can drastically reduce its worth. Professionals in numismatics often prefer coins with their original, undisturbed surfaces, even if they appear dirty. Consult with a qualified coin appraiser or conservator before attempting to clean any coin you suspect might have significant value.
- Presence of Desirable Patina: As discussed, a natural patina can be a protective layer and a sign of authenticity. If the coin has an attractive and stable patina, cleaning it will likely remove this layer, diminishing its appeal and potentially exposing the underlying metal to damage.
- Minor Surface Dirt: For coins with only minor surface dirt or dust, a simple rinse with distilled water and a gentle drying with a soft cloth may be sufficient. Aggressive cleaning is unnecessary for superficial grime.
Preparing to Clean a Brass Coin
If you determine that cleaning is appropriate for your brass coin, gather the necessary materials and prepare your workspace. Always work in a well-lit area. Wear gloves to prevent transferring oils from your skin to the coin, which can cause new tarnishing.
Methods for Cleaning a Brass Coin
When learning how to clean a brass coin, it’s best to start with the mildest methods and progress to stronger solutions only if necessary. Always prioritize gentle handling.
1. Warm Water and Mild Dish Soap
This is the gentlest and often most effective first step for how to clean a brass coin, especially for removing loose dirt and surface grime.
- Procedure:
1. Fill a small bowl with warm (not hot) distilled water.
2. Add a few drops of mild, non-abrasive dish soap (e.g., a dish soap free of harsh chemicals or strong degreasers).
3. Carefully place the brass coin into the soapy water.
4. Allow the coin to soak for 5-10 minutes. This helps loosen dirt.
5. Gently rub the coin’s surface with your fingers or a very soft, lint-free cloth (such as a microfiber cloth). Avoid scrubbing.
6. Rinse the coin thoroughly under warm, running distilled water to remove all soap residue.
7. Pat the coin dry immediately with a clean, soft, absorbent cloth. You can also allow it to air-dry on a soft, clean surface.
- Cautions: Do not use abrasive sponges or brushes. Ensure all soap is rinsed off to prevent residue buildup.
2. Baking Soda Paste
Baking soda (sodium bicarbonate) is a mild abrasive that can effectively remove tarnish without being overly harsh. This method is a common answer to how to clean a brass coin with moderate tarnish.
- Procedure:
1. In a small non-metallic bowl, mix a few tablespoons of baking soda with a small amount of warm water, adding water gradually until a thick paste forms. The paste should be consistent, not watery.
2. Wearing gloves, apply a small amount of the paste to the brass coin.
3. Gently rub the paste over the coin’s surface using your fingers or a very soft cloth. Use light, circular motions.
4. Continue rubbing for a minute or two, observing the tarnish removal.
5. Rinse the coin thoroughly under warm, running distilled water to remove all baking soda residue.
6. Dry the coin completely with a soft, clean cloth.
- Cautions: Avoid vigorous scrubbing, which can scratch the coin. Ensure thorough rinsing, as baking soda residue can leave a white film.
3. Lemon and Salt
The acidity of lemon juice combined with the mild abrasiveness of salt can be effective for removing stubborn tarnish from brass. This is another popular method for how to clean a brass coin.
- Procedure:
1. Cut a fresh lemon in half.
2. Sprinkle a small amount of table salt onto the cut surface of one lemon half.
3. Gently rub the salted lemon half over the surface of the brass coin. The lemon juice and salt will work together to dissolve and abrade the tarnish.
4. Continue rubbing until the desired level of cleanliness is achieved.
5. Rinse the coin immediately and thoroughly under warm, running distilled water to remove all lemon juice and salt.
6. Dry the coin completely with a soft, clean cloth.
- Cautions: Lemon juice is acidic and can be aggressive. Diluting the lemon juice with water (e.g., 1 part lemon juice to 1 part water) before applying can make this method milder and help prevent streaking or over-cleaning. Do not leave the lemon juice on the coin for extended periods, as it can etch the surface or cause discoloration. Rinse immediately after cleaning.
4. Flour, Salt, and Vinegar Paste
This traditional brass cleaning paste combines the mild acid of vinegar with the abrasiveness of salt and the binding properties of flour to create a powerful tarnish remover. This method is often recommended for how to clean a brass coin with significant tarnish.
- Procedure:
1. In a non-metallic bowl, mix equal parts white vinegar, salt, and flour to form a thick, smooth paste. For example, 1/4 cup white vinegar, 1/4 cup salt, and 1/4 cup flour.
2. Apply the paste evenly over the surface of the brass coin using a soft cloth or your gloved fingers.
3. Allow the paste to sit on the coin for 10-15 minutes. This allows the acidic vinegar to work on the tarnish.
4. After the resting period, gently rub the coin with a soft cloth to work the paste and remove loosened tarnish.
5. Rinse the coin thoroughly under warm, running distilled water to remove all traces of the paste.
6. Dry the coin completely with a soft, clean cloth and buff gently to restore shine if desired.
- Cautions: White vinegar is acidic. Do not leave the paste on the coin for too long, as it can cause etching or discoloration. Ensure complete rinsing to prevent residue.
Crucial Considerations and Cautions When Cleaning Brass Coins
Beyond the methods themselves, several overarching principles apply to how to clean a brass coin safely.
Materials to Avoid
Using the wrong materials can cause irreparable damage to a brass coin.
- Abrasive Materials: Never use steel wool, abrasive scouring pads, sandpaper, or stiff brushes. These will scratch the coin’s surface, leaving permanent marks and significantly decreasing its aesthetic and potential monetary value.
- Harsh Chemical Cleaners: Avoid commercial brass cleaners, oven cleaners, drain cleaners, or any strong household chemicals. These can contain harsh acids or alkalis that will strip the coin’s patina, discolor the metal, or even dissolve parts of the coin.
- Metal Polishes: Most metal polishes contain abrasives or chemicals designed to remove significant layers of metal to create a high shine. This is detrimental to a coin’s surface and value.
- Toothpaste: While sometimes suggested for cleaning metals, toothpaste contains mild abrasives that can scratch a coin’s surface, particularly older or softer brass.
- Ketchup: Ketchup is acidic due to vinegar and tomatoes. While it can remove tarnish, its effectiveness is inconsistent, and it can leave residues or cause uneven cleaning.
- Vinegar Mixed with Baking Soda (Directly in a Reaction): While both are used separately, combining them to create a foaming reaction directly on the coin is not recommended. The rapid chemical reaction can be too aggressive and uneven for delicate surfaces.
Testing Cleaning Solutions
Always test any cleaning solution or method on a small, inconspicuous area of the coin first, if possible. This allows you to observe the reaction and ensure it doesn’t cause adverse effects before applying it to the entire surface. For coins, this is often difficult, which reinforces the need to start with the mildest methods.
Thorough Drying
After any wet cleaning method, it is absolutely essential to rinse the coin thoroughly and dry it completely.
- Rinsing: Residual cleaning solution, soap, or acid can continue to react with the brass, causing streaks, discoloration, or even further corrosion. Use warm, distilled water for rinsing to avoid mineral deposits from tap water.
- Drying: Moisture left on the coin’s surface will lead to water spots and accelerate new tarnishing. Immediately pat the coin dry with a clean, soft, lint-free cloth. You can also place the coin on a clean, absorbent cloth or paper towel and allow it to air-dry completely. Some people use a hairdryer on a cool setting to ensure all moisture is gone, holding it at a distance to prevent overheating the coin.
Handling the Coin
Always handle the coin by its edges to avoid touching the main surfaces. Oils and acids from your skin can leave fingerprints that will tarnish over time. Wearing cotton or nitrile gloves is highly recommended.
Storing Cleaned Brass Coins
Once a brass coin has been cleaned and thoroughly dried, proper storage is vital to prevent future tarnishing and damage.
- Airtight Containers: Store coins in airtight, inert containers. Coin flips made of Mylar or polypropylene are good options. Avoid PVC (polyvinyl chloride) flips, as they can leach chemicals that damage coins over time.
- Cool, Dry Place: Store containers in a cool, dry environment away from direct sunlight and extreme temperature fluctuations. Humidity is a major contributor to tarnishing.
- Avoid Paper Envelopes: Standard paper envelopes can contain sulfur, which reacts with brass to cause tarnishing.
Conclusion
Learning how to clean a brass coin involves a balance of effective methods and careful consideration. For common or low-value brass coins, gentle cleaning using household ingredients can restore their appearance. However, for any coin with potential collector value or a desirable patina, the best approach is often to avoid cleaning altogether or to seek professional advice. When cleaning is deemed appropriate, always start with the mildest methods, proceed gently, and prioritize thorough rinsing and drying to preserve the coin’s integrity.
How to make brass coins shiny?
From my experience, Place your coin pendant in the batter. And let it sit for a few minutes. Remove your coin pendant and rinse it off.
Can I use Dawn dish soap to clean brass?
You don’t need anything special for brass cleaning… i just use a 5 gallon bucket filled with hot water and dawn dish detergent , with maybe a little lemishine if i am feeling OCD and want nice shiny brass.