It was more than the daily milk baths that she took. It was actually the sour milk that was in the bath.
Sour milk has lactic acid, which is now used as one of the chemicals for peeling facial skin.
It removes the top layer of skin and with it the brown pigments, fine wrinkles, and skin irregularities. There are many methods available for skin resurfacing. Chemical peels denature cells in the top layer of skin, while dermabrasion abrades them away. Laser, which is the latest technique, removes superficial skin by evaporating it. Each one of these techniques has advantages and disadvantages.