Liver of Sulphur creates a rainbow to black oxidised patina on fine silver, sterling silver, copper bearing metals including brass, and bronze. Liver of Sulphur should be used very carefully. Patina Gel Liver of Sulphur emits a strong rotten egg odour when mixed into solution. The odour is not harmful as long as the solution is not boiled or burned, but it is wise to avoid breathing fumes of any kind. Work in a well ventilated area. Hasten the air exchange with an open window or exhaust fan. DO NOT BOIL OR BUN PATINA GEL OR THE PATINA GEL SOLUTION. Heating will emit sulphur dioxide, which is a poison when inhaled. See MSDS online for further safety precautions and always wear gloves and eye protection.