Benzoyl Peroxide, Clindamycin Phosphate, & Salicylic Acid Bar Soap combines most of the effective agents in treating acne. Benzoyl Peroxide works best on red, pus-filled pimples. It works by removing excess oil and dead skin cells, and helps kill acne-causing bacteria beneath the skin. Salicylic Acid works best on blackheads and whiteheads. It works by removing dead skin cells which clog pores and contribute to acne breakouts. Clindamycin Phosphate, an antibiotic works by penetrating into the skin and killing acne-causing bacteria.