A professional who tends equipment that washes animal stock (animal skins, splits, fleshings, and trimmings) used to make glue and gelatin. Respnsibilities include:

• Turns valve to start continuous flush of water into tub to wash foreign materials from stock.
• Turns handwheel to actuate roller that kneads and turns stock in tub.
• Turns off water and roller after time necessary to reduce foreign material to required level.
• Drains water from tub and pumps specified amount of acid into tub to kill organisms in stock.
• Tests concentration of acid-sample in tub, using titration, burette, and pH indicator, and adds acid to tub when necessary.
• Drains acid from tub after prescribed time and washes stock with water.