There are a few things you can do to clean powder coated metal. The first is to use a mild soap and water solution to clean the metal. This will remove any built up paint or other contaminants that may have been on the metal. Next, use a wire brush to scrub the metal with a light amount of soap and water. Be sure to work in small areas at a time, as too much soap will cause the metal to become dirty and difficult to clean. Finally, use a dry cloth or paper towel to dry the metal.