Forming clay into pottery helped the earliest human cultures exist. From food and water storage containers to art and cultural objects, pottery has helped to advance societies. As the pots and ritual objects became more detailed, carvings, stampings and other aesthetic modifications were developed to improve the pottery’s design. Today, carving pottery is primarily used to increase the clay object’s artistic or decorative value.
Use tools specially designed for clay. There are many different types of clay tools available from clay centers and craft shops. You can buy sets of carving tools that the manufacturer has selected to cover most of your needs when carving. For basic to advanced surface carving use a small tipped pen tool, a scoring tool, square and circle hole making tools, thin cutting knives, a sculpting knife, a serrated knife, a fettling knife, trim tools for throwing, ribbon tools, and wire loop tools. For very intricate carving, such as sculpting the human face, use rubber tipped clay modeling tools.
Decide what type of clay to work with. Lighter grog clays like porcelain have a very smooth consistency and are therefore easier to carve but more likely to brake when thin. Heavier grog clays like stoneware have more structure and will take more pressure and sharper tools to work with when in a leather hard state.
Decide what state of clay to work with. You can carve clay when it is wet or leather hard. Throw a pot on the potter's wheel or hand build a form and carve it while wet. This allows for very fluid movements but a lack of control as you can not handle your piece. Wait for it to dry a few hours depending on its thickness and carve your design while the clay is leather hard. You can apply more pressure to the piece and handle the pot at any angle when it is in this semi-hard state. If the piece gets too dry it becomes greenware and you can add some water to the area where you're working to soften the clay.
Use the tools for what they were designed for. The pen tool is one of the most versatile tools used in carving pottery. Use it to cut through any thickness of clay and score contour line drawings. Use hole making tools to take out large portions of clay or punch holes. Knives add texture to the clay's surface and can cut clay for large shape alterations. Trim tools are used to cut away excess clay from the piece when throwing on the wheel, but you can use them to hollow out the surface of clay in square or rounded shapes. Ribbon and wire loop tools are thin strips of wire that are molded into shapes on the end of a wood handle. Use them to add shapes as stamps, or remove clay in interesting patterns from the surface. Use rubber modeling tools to carefully shape the clay into facial features or natural textures such as tree bark or hair.
Experiment with household tools. Forks, spoons, pen tips, wine openers, and other wood and metal objects around the home are great for different line qualities and carving possibilities.