Dry your piece of clay. This can be done in air or in the room. This process will help to make the roasting more even. Complete drying can take from several hours to days depending on the size of the product and whether it's hollow.
Use the simplest method - baking in the fire. This method is suitable, for example, a small clay toys. Take a jar, put inside a piece of clay and place it into the fire. Before this clay toy is best heated in the oven or near the fire. This will help it not to crack. The firing results can be worse than in a special oven, but it will reach the desired temperature. It may be easier if the fires are stoked in a confined space such as a grill or inside brickwork. This will make the kiln more stable in terms of temperature.
If possible, use a special muffle kiln. It has the ability to regulate temperature. The first two hours of firing it should be no more than 200 degrees. Then for 6 hours to gradually raise the temperature to 1000 degrees. Then turn it off and allow the product to cool. That way you can avoid cracks and excessive darkening of the clay.
If you have in the house Russian stove place your pottery for firing there. It is sufficient to put inside a few logs to fire up the furnace and leave there product in the tin to cool the stove.
After baking you can paint your toy or jar, cover with icing and use for different purposes. Fired clay is suitable, for example, for a wound in her fluids.
Try not to use for baking an ordinary electric or gas oven. There can not reach the required temperature for completion of all chemical processes in the clay.