This process, which is repeated a number of times and carried out by machines that are ever more technologically advanced, enables the separation of the coarse rougher hairs and other remaining impurities from the soft downy fleece. The longer fibres (mm 38/40) are the first to come through the processing, the shorter fibres emerge after the subsequent passages. Shorter fibres are obtained either through the dehairing process, where the resulting quality is generally good, or from tanning, where the fleece is collected from the dead animal, particularly at the end of the season.

These latter fibres often contain more impurities, such as pieces of skin and dandruff, and may be coarser to the touch due to the application of chemical products that are used to detach the fibres from the skin.

The use of such chemicals may alter the morphological composition of the fibres which may even result in errors of identification of the same fibre.

It is also interesting to see how no material is wasted during processing. In fact, the coarse hair will be collected and utilized in the production of other articles such as brushes and a type of stuffing that is used between flooring and carpets.