What Kind of Exfoliator Do You Prefer?

Recently, Yum and I were discussing the merits of facial exfoliators. Physical exfoliators use an abrasive ingredient like crushed seeds or nuts, sugar, or beads to exfoliate the skin. Chemical exfoliators rely on things like citric or alpha hydroxy acids to do the sloughing. Both kinds of exfoliators essentially do the same thing, but which type do you prefer?