The woolen and worsted process both require that the wool (and other similar animal fibers, cashmere, camel, etc.) be cleaned before mechanical processing. Woolen and worsted nomenclatures apply only to the textile processing of animal fibers, but it has become common to include fiber blends under these terms.

The resultant fabrics will be classified as being either woolen or worsted, but this designation is assigned during fiber processing and yarn formation, not in the cloth or finished garment.

 Woolen yarn formation is also very common for knitwear, where the resultant garment has some bulk and the requirement for visual aesthetics (of fiber alignment) is minimal.

The worsted processing route is more complex and requires the removal of short fibers and the use of a focused mechanical process to make the individual fibers parallel to each other. The yarn formation process is significantly more comprehensive and results in a very sleek yarn which will offer a clean looking woven fabric, such as for suitings. The worsted process is significantly more expensive and is seldom used for knitwear.