Raku fired pots are taken out of the kiln when the clay is red hot, and then subjected to a number of treatments whilst still hot. My favoured technique is to glaze the pot before firing, then when it comes out of the kiln to plunge it into a bucket of sawdust and put the lid on. The heat of the pot ignites the sawdust, but there is a shortage of oxygen. This causes reduction in the clay and glaze, where oxygen leaves the pot to feed the flames, giving a range of dramatic effects not easily achieved by other means.
Note that to survive the shock of being taken out of the kiln at high temperature the clay has to be quite coarse and open. This, combined with the relatively low firing temperature, means that many of these pieces are not waterproof, so should not be used for food or drink, flowers (except dried) or plants. If a piece is fully waterproof, that will be stated in the description. Also, note that some of the bright, lustrous colours obtained from copper and other metals may slowly fade with time if the piece is positioned in sunlight or strong light.