Aqueous scouring involves passing the wool through a series of tanks (bowls). The first few bowls contain hot detergent solution and the remaining bowls are used to rinse the wool. Basically scouring is a multi-stage countercurrent extraction process.

Contaminant removal occurs in a number of stages:

• First the contaminants are penetrated by water and detergent followed by rapid swelling of the wool wax and proteinaceous contaminants along with dissolution of some of the water-soluble suint.
• Second, wax globules are formed within the swollen mass.
• Third, complexed and uncomplexed contaminants that are not strongly bound to the fibre surface (easy-to-remove contaminants) are swept from the fibre surface.
• Fourth, harder-to-remove contaminants, such as swollen proteins, oxidised wool wax and less soluble suint residues either complexed or uncomplexed, are partially removed.