All colors in the Potter's Choice series are LEAD FREE. CL glazes restricted from use K-6 (ASTM D-4236/LHAMA) Cone 5-6. The Potter's Choice series is a collection of potters' favorite glazes made easy. These glazes are fired in an oxidation kiln. They are made for anyone who would like to achieve the Cone 10 reduction effects without having to have a reduction gas kiln or firing at that high temperature. The PC Series glazes look beautiful and authentic. They work well over any of the AMACO® stoneware or porcelain clays. Special application instructions: PC-20: Blue Rutile needs to be applied heavy. Apply at least four coats. It will flow just a little and create beautiful effects. PC-50: Shino needs to be applied irregularly. Apply two irregular coats. Once you have used it awhile you will see the effects you can get by varying the application. PC-60: Salt Buff has to be applied on the thin side. No more than two irregular coats are needed to get the random effect of salt glazing. AMACO® Liquid Underglaze Decorating Colors are available in 2 oz. jars.