Potters Modelling White Clay is a grey/white colored stoneware blend. It is very easy to work with and non-toxic, making it perfect for arts, classroom and school use. Choose between air-drying or kiln firing (firing range of 1220-1280 degrees celsius). Wet to dry shrinkage 5-8% and around 16% when fired. Ensure the bag is kept sealed to prevent the product from drying out. If the clay has been left out of the bag for a few days and has become a little firm it can be dropped from waist height a number of times to soften the clay and bring it back to life.