Castoreum
Castoreum is used in perfume-making. It is used to describe the solution from the alcohol-tinted and dried beaver castor. Dried beaver castor sacs are aged for two or more years. They are aged to soften. They are also aged for their harshness to vanish. In the science of perfume, castoreum is mainly used as a smell for leather. It is often used with other ingredients. There are some classic perfumes that use castor. They are Emeraude, Coty Chanel Cuir de Russie, Magie Noire, Lancôme Caractère, Hechter Madame, Carven, Givenchy III, Shalimar, and many "leather" perfumes.