Dolan Tools: #220S Flexible Knife Sheffield Pottery offers the complete line of Dolan Tools for clay. Dolan Potters tools are meticulously formed and sharpened using methods only used by Dolan Tools. The fine edge of a Dolan Tool is tempered and treated to withstand the vigors of clay work. They are high-carbon knife grade steel. The tool heads are coupled with a fine lathe turned hardwood handle. We believe using your tools often is the best way to keep your tools in optimal condition. With continual use, rinsing after handling, and storing them in a dry place, you will retain the quality and prolong your tool's life. If you find yourself in a position where you may not use them for a while, we recommend coating them in a fine layer of oil, any oil will do. If for any reason you decide on sharpening your tools we caution that the edge of each of the ceramic tools we make are refined to a razor's edge. Use the utmost care while sharpening to avoid any injury that may occur. In order to sharpen your tools we recommend three methods. One, use an oil or water whetstone. Two, use a diamond file. Or three, send your tools back to us and we will restore your edge.