Appropriate for all hair types, the ingredient list of the new Sunday Riley Clean Rinse Clarifying Scalp Serum (£42) reads like a serious skin-care treatment. The rinse contains glycolic acid, salicylic acid, niacinamide, witch hazel, rose clay, zinc salt, essential fatty acids, and jasmine essential oil, all of which work together to break down dead skin cells and product residue, clear out any gunk in your pores, and hydrate and soothe your scalp. The fact that it has a micellar-water base and a small nozzle means it's great to use if you wear your hair in a protective style.