Professional Oytra 10 Color POLYMER Bake and Set Clay 10 Grams each block. Semi Hard Initially. You need to pay a little and make it soft. You can mould it into desired shapes and then bake it. How to use the clay: 1. Place onto a foil sheet or ceramic tile and into the centre of a household oven, pre-heated to 130-150 degrees C(260-300 degrees F) for 30 minutes. 2. Carefully move from the oven and let it cool. 3. Baking time may vary according to clay thickness and as a general rule allow 30 mins baking time for every 6 mm thickness. 4. Note: it is advisable to bake a test ace before baking your artistic work. 5. Hardened clay will accept consecutive layers of clay over it and can be rebaked. 6. Once hardened it can drilled, sanded, cut and painted and is washable with soapy water. 7.Store unused clay in a cool dark ace and keep wrapped in an airtight container.