how to make copper turn brown
5. Mix a brown patina solution instead. This solution will turn your copper a darker brown, roughly the color of an American penny. Simply shake baking soda in a bottle of hot water one spoonful at a time, until additional baking soda does not dissolve.. Use tongs to dip the copper into the liver of sulfur solution for a second or two. Using gloves and tongs, or tweezers for small items, hold the copper under the surface of the liver of sulfur and water solution for a short time.