Copper items, lamps, fixtures and outdoor projects can be made to look weathered by use of paints or chemicals. For example, a 50/50 mix of ammonia and white vinegar will give copper an aged patina. Architects and craftspeople use copper sulfate on copper items to make them look old. Patina Green is another product used to give copper an instant aged look. Woodworkers and wood finishers mix their own wood stains. This is to match finishes on wood furniture to the same color, tone and patina of the original finish.