The larger stems of herbs and leaves should be discarded, as they possess little or no value, and leaves that are partly dried from age or that are discolored or injured by disease or insects should be excluded if the best price is to be obtained. The material must be carefully dried. All plant material, in whatever form, is easily spoiled in both appearance and value if improper methods are used to remove the large quantity of moisture that is usually present. Fleshy roots dry very slowly and frequently become moldy unless they are sliced across or lengthwise to permit more rapid evaporation of the moisture. In the drug market such roots occur m various forms, and information on this point should be secured from the dealers or from experienced collectors so that the dried material may conform to market requirements.
Leaves readily lose their green color while drying and sometimes become brown or even black.
They should, therefore, be spread out in a well-ventilated room, especially in cloudy weather, and dried as rapidly as possible. Exposure to direct bright sunlight is undesirable because it frequently causes bleaching of the leaves. Fruits, particularly those that are juicy, are especially difficult to handle on account of their tendency to become sour or moldy. They should preferably be spread out in thin layers on wire or cloth screens that will permit a thorough circulation of air end on which they can be frequently stirred. The best way to store the dried material is to pack it in clean bags or boxes.