(1) Mechanical degreasing method

This method mainly uses a large or small meat removal machine to remove a large amount of fat in the subcutaneous layer, so that free fat and sebaceous glands are mechanically squeezed and damaged. Destroyed, the grease is pressed out and removed. In addition to using a meat remover, roller presses and presses can be used to remove oil from the skins. The pressure of the press is 30 kg/cm2.

(2) Chemical degreasing method

It is a method of removing grease by using a degreasing agent to saponify, emulsify or hydrolyze grease. This method is usually carried out in a groove or drum.

Saponification method

This method uses alkali to saponify the oil inside and outside the skin and on the coat. The products generated are soap and glycerin. If a strong alkali is used for degreasing at a higher temperature, the cutin of the hair will be destroyed, causing the hair to lose its luster, become fragile, or cause the hair to be hooked, so it cannot be used in fur degreasing operations. For mink skin, the amount of soda ash used for degreasing should be small and used together with a certain amount of surfactant to achieve a better degreasing effect.

Emulsification method

This method is the most commonly used method for fur degreasing. The most commonly used surfactants are soap powder, soap, detergent AS, and washing powder.

Hydrolysis method

This method uses lipase to treat rawhide at a certain temperature, concentration and pH to hydrolyze fat into glycerin and fatty acids to achieve the purpose of removing fat. Apollo 100-C from Lowenstein USA is an enzyme soaking agent. It can accelerate water immersion and remove fat without causing hair loss.

Solvent method

This method uses the property of grease to dissolve in organic solvents for degreasing, such as kerosene, gasoline, etc. Safety must be paid attention to in this method.