Because the bag maintenance is polished and waxed every once in a while, it will not show the change of skin. I want to be careful that the bag should not be exposed to the sun, baked, squeezed or touched with sharp tools to prevent surface deformation, discoloration and scratches. Changing skin is another matter. Skin exchange is a repair technology for this situation. It can make the old part of the bag glow again, and make the bag thoroughly remould itself and glow with new brilliance.