This finely ground Calcium Carbonate (98% pure) is a must-have for stained glass cleanup and glazing work. Whiting absorbs excess flux, patina, and oils, making it easy to clean and polish solder lines. Also used in high-quality glazing compounds and for post-glazing cleanup. Weight: 5 lbsNaturally contains small amounts of silica or magnesium. ⚠️ PROP 65 WARNING:Cancer and Reproductive Harm — www.P65Warnings.ca.gov Perfect for:✔ Studio cleanup & solder line polishing✔ Glazing compound preparation✔ High-volume stained glass work FREE US SHIPPING on orders over $100 USD, any international orders you are responsible for duty fees and extra shipping costs. Any over charge for shipping will be refunded once actual shipping is calculated!