Tanners program and use tannery drums. They perform the work according to the work instructions, verify the physical and chemical characteristics of the hide, skin, or leather and of the liquid floats (e.g. pH, temperature, chemicals concentration) during the process. They use the drum for washing the hide or skin, removing the hair (not in the case of hides and skins tanned with the hair or wool on), bating, tanning, retanning, dyeing and milling.