To bake polymer clay, it is important to follow the manufacturers recommended temperature and baking time, which can vary depending on the brand of clay. Most brands recommend baking polymer clay at 275°F (135°C) for 15 to 30 minutes per 1/4 inch of thickness. It is important to ensure that the oven is preheated to the correct temperature and that the temperature is accurate using an oven thermometer. Thinner pieces of clay should be baked for a minimum of 20 minutes at low temperatures of 200°F (93°C) or less. It is also recommended to avoid placing clay onto any kind of paper, as it can leach out and soak up the oils, making the clay dry and brittle.