The wool is sorted as to fineness, crimp, length of fiber, and felting qualities. Dirt, suint (dried perspiration), and lanolin are removed by a soap-alkali scouring; by the expensive naphtha solvent method, which retains the full strength and softness of the fiber; or by freezing and shaking. Wool may be carbonized to remove vegetable matter. It is bleached and dyed as raw stock, yarn, or in the piece; it is oiled to withstand processing and is often blended.
Woolen goods are woven from carded short-staple fibers into soft yarns adapted to fulling and napping. Worsted fabrics such as whipcord, gabardine, and serge have a hard, smooth texture. Originally made only from long-staple fibers, worsted yarn is now spun also from medium or short fibers. The fibers are carded, the resulting sliver gilled to straighten the fibers and double them for uniformity; subjected to successive combings to remove nails (short ends) and lay the fibers parallel; then drawn into roving and spun, usually by the rapid, continuous ring method, and twisted. Although the twill weave is usual for worsteds, the same weaves may be used as for woolens without the pattern being obscured by the napping, fulling, and shearing processes commonly employed in finishing woolens.