Various objects such as grains, wooden utensils, things made of bone, cloth, liquids, metals, skins and earthen objects are purified by time, by the wind, by fire, by earth and by water, either separately or in combination. It was said that objects could be purified by other objects. That is explained. Asthi means ivory etc. Rasa means oil and ghee. Taijasa means gold and other precious metals. Grains, wood, ivory, cloth, liquids like oil and ghee, precious metals, skins and earthen objects like pots and bricks become pure by time, wind, fire earth and water according to scriptural rules. These purifying agents may be used in combination or singly. Thus metals are purified by earth, water and fire as well. Wool cloth is purified by air alone.