Fill a small plastic container with warm tap water. Add a small squirt of dish soap. Gently place your coin in the water and use your fingers to softly scrub the dirt from the center of the coin outward towards the edges. Do this until your coin is clean. Then rinse in either hot tap water or distilled water. Now gently pat the coin dry. Be very careful while you are cleaning and drying your coin that you do not scratch it.