Quick Tips
Cleaning pennies can be surprisingly nuanced, depending on whether your goal is preserving their historical charm (patina) or making them sparkle like new. Here’s an expanded, practical guide to cleaning pennies, including natural home remedies, chemical cleaners, methods professionals employ, batch cleaning advice, safety tips, and essential warnings.
Before You Begin: Identifying Your Pennies
Understanding your penny’s composition is crucial. Pennies minted before 1982 are primarily copper, whereas those minted after 1982 are mostly zinc coated with copper. Copper pennies tolerate cleaning well, but the thin copper layer on zinc-based pennies can easily be damaged if cleaning is too aggressive, requiring gentler techniques.
Choosing the Right Cleaning Method
The purpose behind cleaning your pennies largely dictates the method you should employ. For coin collectors, minimal cleaning—distilled water and gentle brushing—is advisable to preserve value. If your coins are for crafting, displays, or decorative purposes, you might prefer natural acid-based methods like vinegar or lemon juice, or gentle polishing techniques such as baking soda paste. Science experiments often involve comparing different cleaning methods, making vinegar and salt ideal for visibly demonstrating chemical reactions and immediate results.
Single Penny vs. Batch Cleaning
Cleaning a single penny allows you more precision and care. Methods such as ketchup application, gentle eraser rubbing, or baking soda polishing paste are ideal here. These methods permit targeted attention to detail, ideal for valuable or sentimental coins.
Batch cleaning requires efficiency and uniformity. Methods like the vinegar and salt soak are ideal for cleaning multiple pennies simultaneously. When batch cleaning, spread pennies evenly in a shallow solution to ensure each coin is equally exposed. Avoid stacking coins directly on top of each other, as it can result in uneven cleaning or potential coin-to-coin damage. After soaking, thoroughly rinse batches of pennies under running water, ideally using a colander or strainer for efficiency, and dry them carefully by spreading on a soft cloth to air dry.
Natural Home Remedies for Shiny Pennies
One popular method involves a simple vinegar and salt solution. In a non-metal container, mix approximately ¼ cup of white vinegar with one teaspoon of salt until dissolved. Submerge your pennies in this solution briefly, typically 30 seconds to two minutes. Carefully observe to avoid over-cleaning. After soaking, rinse the pennies thoroughly under running water to remove any residue and pat dry gently with a soft cloth. This method is quick, cost-effective, and works exceptionally well for multiple pennies, but be aware it entirely removes the natural patina and can harm the coin surface if left too long.
Lemon juice is another natural cleaner you can use similarly to vinegar. Replace vinegar with lemon juice and follow the same process. Lemon juice often provides a brighter finish and has a pleasant aroma, although it also completely strips patina and can cause discoloration if pennies remain submerged excessively.
An amusing yet effective method is using ketchup. Apply a thin layer of ketchup over your pennies and allow them to sit for one to two minutes. Gently scrub with a toothbrush to lift away oxidation and grime. Rinse thoroughly and dry carefully afterward. This method is fun, especially for children, but messy and impractical for cleaning large batches of pennies.
Baking soda paste offers a gentle abrasive method. Combine baking soda with a little water to form a paste, then gently rub it onto your pennies with your fingers or a soft cloth. This method provides excellent polishing effects but be cautious; baking soda can create microscopic scratches on the coin’s surface.
Cleaning Pennies While Preserving Patina
If you aim to preserve the penny’s original patina and potential collector value, gentle methods are best.
- Begin by rinsing the penny under distilled water to loosen and remove superficial dirt.
- If needed, prepare a mild dish soap and distilled water solution, allowing the penny to soak for several minutes to soften stubborn grime.
- With a soft toothbrush, gently scrub under water, focusing on dirt removal without damaging the coin surface.
- For persistent dirt, use a wooden toothpick or cotton swab to gently lift it away.
- Finally, rinse again with distilled water or pure acetone to eliminate any residue, and carefully dry the penny without rubbing, using a lint-free cloth or allowing it to air dry.
For heavily corroded pennies, collectors sometimes recommend soaking in olive oil for an extended period (days or even weeks). This gentle method slowly penetrates corrosion, making it easier to remove without damaging the underlying metal. After soaking, gently brush away loosened debris, rinse with water, and dry softly.
Professional and Commercial Chemical Cleaners
Professionals sometimes resort to specialized chemical cleaners for particularly challenging cleaning tasks.
- One commonly used product is E-Z-est (Jeweluster), a potent chemical dip. When using this cleaner, immerse pennies for only one or two seconds, then immediately rinse thoroughly in water and neutralize any residue with a baking soda solution. Always handle with gloves and eye protection, working in well-ventilated areas to avoid fumes. This method is swift and effective for removing heavy tarnish but can also strip away minute layers of metal and harm the penny’s luster if misused.
- Another professional tool is an ultrasonic cleaner, popular for cleaning large batches of coins gently. These devices use vibrations in water or mild detergent solutions to loosen surface dirt efficiently without direct abrasion. Ultrasonic cleaning is gentle on the coin surface, excellent for removing superficial dirt but will not significantly impact heavy oxidation or discoloration.
Important Warnings and Mistakes to Avoid
- Never use harsh abrasives such as steel wool, sandpaper, or metal brushes. These items can deeply scratch and permanently damage pennies, dramatically reducing any potential collector value. Similarly, strong chemicals such as bleach, ammonia, muriatic acid, or untested chemical mixtures can severely damage coins or produce hazardous fumes. Additionally, never employ motorized tools like Dremel drills or power buffers, as these can irreparably harm the coin surface.
- Avoid prolonged soaking or repeated exposure to aggressive cleaners, especially acidic solutions, as this can etch or alter the penny’s surface significantly. Valuable coins should generally remain uncleaned unless you consult with a numismatic professional. Over-cleaning can permanently devalue coins, particularly rare or collectible ones.\
- Safety should always be your priority during the cleaning process. Always wear gloves, especially when using chemical cleaners or acidic solutions, to protect your skin. Ensure adequate ventilation to avoid inhalation of fumes, particularly when using potent chemical products. Additionally, wear protective eyewear to guard against accidental splashes.
Aftercare and Storage
Proper aftercare is essential to maintain your cleaned pennies. After cleaning, thoroughly rinse and completely dry pennies to prevent future corrosion or spotting. Handle coins gently by their edges or with gloves to avoid fingerprint oils, which can cause spots and further oxidation. For storage, choose coin flips, capsules, or acid-free holders specifically designed for coins. Proper storage prevents exposure to moisture and airborne contaminants, prolonging the life and appearance of your cleaned coins.
Professional Insights and Final Thoughts
Experienced numismatists universally agree that minimal cleaning is best, particularly for valuable or historically significant pennies. Aggressive cleaning almost invariably lowers numismatic value, even if it results in a visually appealing, shiny coin. However, for common or decorative coins, feel free to experiment responsibly with various cleaning techniques, keeping a record of your methods and results for future reference. Understanding the balance between cleaning for appearance and preserving historical integrity is key to effective penny cleaning.
Cleaning pennies, therefore, can be an engaging process that blends chemistry, history, and artistry. With patience, care, and appropriate methods, your cleaned pennies—whether polished brightly or carefully preserved—will continue to tell their unique stories.