Clay preparation by kneading to remove air and softening it into the correct condition for the potter. The procedure is called wedging or kneading the clay. The blocks of harder and softer clays are wedged by continually cutting, rotating and slamming them back together. In Chinese porcelain potting the clay was often mixed, softened and prepared by feet, by stepping into it. Rough clays could be kneeded by water buffaloes walking into it. The machine doing this work today is called a pugmill, which looks pretty much like a meat mincer.