How to Clean Penny Coins Without Damaging Them

What You’ll Need

A small bowl or clean sink
Lukewarm water—not hot
A few drops of mild dish soap
A soft, lint-free cloth or paper towel for the work surface
Clean hands, or disposable gloves if you want to avoid transferring oils
Optional: a second bowl of clean water for rinsing

Use these supplies only for ordinary pennies that you want to make less dirty, not to restore a shine. Pennies are usually copper-plated zinc in modern U.S. circulation, while older U.S. cents can have a different composition. The finish and condition matter, so do not assume every penny will react the same way.

Step-by-Step

Decide whether to clean it. If the penny may be collectible, unusually old, rare, or part of a collection, stop before washing it. Cleaning can scratch the surface, strip or alter its patina, and leave hairline marks that collectors notice. If you are unsure whether it has value, ask a reputable coin dealer or numismatic organization for guidance without polishing it.
Prepare a protected workspace. Work over a bowl or a sink with the drain covered. Pennies are small and easy to lose, and hard surfaces can scratch a coin if it is dropped. Keep other coins separate so they do not rub together during cleaning.
Mix a mild soap solution. Add a few drops of ordinary dish soap to lukewarm water. You need only enough solution to wet the penny. Do not add vinegar, lemon juice, salt, baking soda, bleach, or metal polish; these can chemically change the surface or abrade it.
Wet the penny gently. Place one penny in the water and let it sit briefly, just long enough to soften loose grime. There is no need for a long soak. Avoid hot water and do not boil the coin; heat and aggressive treatment can damage its surface, especially if it is a modern copper-plated cent.
Lift dirt without scrubbing. Hold the coin by its edges and use your fingertips to move the soapy water over it. If grime remains, let it soften a little longer and repeat the gentle motion. Do not use a toothbrush, scouring pad, pencil eraser, knife, or other tool: even a soft-looking brush can leave fine scratches.
Rinse with clean water. Move the penny to a second bowl of clean lukewarm water, or rinse it gently under a low flow. Remove soap rather than rubbing it off. If you use a sink, keep the drain covered and hold the penny securely by its edges.
Blot it dry. Set the coin on a clean, soft cloth or paper towel and gently blot the water. Do not rub, buff, or drag the penny across the cloth. Let it air-dry completely on a clean surface before storing it, so moisture is not trapped against another coin or in a container.
Check the result and stop. If the penny is still dark, stained, or discolored, accept its natural appearance rather than escalating to stronger cleaners. Some discoloration is oxidation or a change in the metal’s surface, not removable dirt. A clean coin does not need to look bright or new.

Common Mistakes

Cleaning a coin that should be assessed first: A shiny result is not the same as a better coin. Removing original surface color or leaving scratches can lower collector appeal and value. Do not clean a coin just to make a date or design easier to see.

Using acidic kitchen ingredients: Vinegar and lemon juice can react with copper and alter the surface. Salt can contribute to corrosion, while mixing ingredients creates an unpredictable treatment. A quick online cleaning trick may make a penny look brighter but permanently change it.

Scrubbing or polishing: Rubbing can leave fine parallel marks, dull raised details, or remove the original finish. Abrasive powders and metal polish are especially unsuitable, even when the coin looks heavily soiled.

Soaking for too long or using heat: Extended soaking is unnecessary for ordinary dirt and may worsen damage, particularly on coins with plating or existing corrosion. Never boil pennies or use a dishwasher, ultrasonic cleaner, or chemical dip.

Expecting every stain to come off: Dark color, green deposits, or patchy areas may reflect corrosion or a reaction with the coin’s surface. Trying stronger products can make the damage more noticeable. If a deposit is crusty or the coin is potentially valuable, leave it alone and seek expert advice.

Tips

Handle pennies by their edges. Finger oils can leave marks, especially on a clean or collectible surface.
Clean one coin at a time. Coins rubbing together can scratch each other, and separate handling makes it easier to notice changes.
Keep the process gentle and brief. The goal is to loosen surface dirt, not to restore the coin’s original color.
For a collection, use a suitable coin holder or album and avoid touching the faces. Do not put wet coins into storage.
Do not mix different metals in a cleaning bath. If you are cleaning several ordinary pennies, rinse the bowl between batches and check each coin for signs of damage.

Troubleshooting

The penny still looks dull: Stop there. Dullness may be part of the coin’s natural surface or oxidation rather than removable grime. More cleaning is unlikely to improve it safely.

A green or crusty patch remains: Do not scrape it off or apply acid. The deposit may be corrosion, and removing it can take away metal or damage the coin. Keep the coin dry and, if it may be valuable, ask a coin professional how to proceed.

The surface looks scratched or streaky: Further rubbing will not reverse the marks. Rinse away any remaining soap, blot dry, and avoid polishing. If it is collectible, disclose that it has been cleaned if you later have it assessed.

The penny has a coating or unusual appearance: Stop washing if the surface flakes, bubbles, or changes color. It may be damaged, plated, or otherwise different from a typical circulating cent. Do not experiment with solvents or stronger cleaners.

You dropped it near the drain: Do not run water while trying to retrieve it. Cover the drain before continuing, and use a safe way to recover the coin rather than reaching into plumbing or using a sharp tool.

Frequently Asked Questions

Can I clean a penny with vinegar?

It is not recommended. Vinegar is acidic and can alter the copper surface, so the result may be discoloration or damage rather than a safe cleaning.

Can I use ketchup or lemon juice to clean pennies?

Neither is a good choice. Their acids and other ingredients can react unpredictably with the metal and may leave a permanently changed surface.

Should I clean an old or collectible penny?

No. Leave it as found until its value and condition have been assessed. Improper cleaning can reduce collector value even if the coin looks brighter afterward.

Why did my penny turn darker after cleaning?

Water, soap, rubbing, or a reaction with the coin’s metal may have changed its appearance, or the dark color may be part of its existing oxidation. Stop cleaning; additional treatment can cause more damage.

Can I clean pennies with toothpaste or baking soda?

Avoid both. They can act as abrasives and scratch the coin, while rubbing them into the surface can remove its original finish.

How should I store a cleaned penny?

Let it air-dry fully, then store it separately in a clean coin holder or other suitable container. Avoid loose storage where coins can rub together, and keep collectible coins uncleaned.

Further reading: American Numismatic Association. Details can change, so check the official page for anything that matters to you. Spotted a mistake? Tell us. How we write an answer.