In some rural parts of Cambodia, hulling or husking rice is done with a device consisting of two baskets, although this device has largely been replaced by a mechanized rice mill. The interior of the smaller basket is coated with clay, in which vertically fixed bamboo strips jut out about one centimeter. The upper basket is pierced near its center with a hole through which the rice is poured. The rice, pushed outward by the rotating movement is husked by passing between the jutting bamboo strips. After hulling, the rice is winnowed and pounded. This operation is necessary for polishing rice and separating it from dirt and the husks that remain after hulling. It is typically done with a wooden or stone mortar. Twenty-five to fifty liters of rice are put in the mortar, and then the rice is ground with a large wooden pestle, usually operated by hand. The rice must be winnowed one last time before it becomes edible.