Black Patina EX is a chemical used to blacken solder joints. It is a favorite in stained glass classes nationwide. Apply it by wiping it on with a cloth. Black Patina EX is not classified as a poisonous or hazardous substance, so it can be handled without documents such as a "Poisonous and Deleterious Substances Transfer Certificate." It is a patina with high fixing performance. It is a chemical used to blacken solder joints. Apply it by wiping it on with a cloth. If time has passed since the soldering work, an invisible oxide film may have formed. Also, touching the work during the process may leave hand oils on the solder joints. If "deoxidation" to remove the oxide film and "degreasing" to remove oil and grease are not done properly, the staining may be uneven. Please polish the work well before use. Depending on the amount of pre- and post-treatment, you can achieve a subdued black or a glossy black finish.