slough off (someone's) skin

Translations
сбрасывать (чью-то) кожу
The snake will slough off its skin several times a year.
Змея сбрасывает свою кожу несколько раз в год.
Definitions
To shed or remove the outer layer of skin, often as a result of injury, disease, or a natural biological process. In a figurative sense, it can also mean to get rid of something unwanted or unnecessary.