Gather your materials:
You will need a soft-bristled brush, mild dish soap, warm water, and a soft cloth.
Mix a solution of warm water and mild dish soap: Mix the water and dish soap in a small container or bowl. The soap should be mild enough that it won't damage the coin, but strong enough to remove any dirt or grime.
Use the brush to gently scrub the coin:
Dip the brush in the soapy water and gently scrub the coin, paying special attention to the crevices and any areas that appear dirty. Use a soft brush to avoid scratching the coin.
Rinse the coin with clean water:
After you've finished scrubbing, rinse the coin with clean water to remove any remaining soap or dirt. Dry the coin with a soft cloth: Use a soft, lint-free cloth to gently dry the coin. Be sure to dry both sides of the coin, and take care not to rub too hard.
Store the coin properly:
Once the coin is dry, store it in a safe place, away from direct sunlight, moisture, and extreme temperatures.
Note: It's important to be gentle when cleaning gold coins as they can be easily scratched or damaged. If you're unsure about cleaning a coin, it's best to consult with a professional coin dealer or numismatist for advice.