We recommend you clean your brush once a week. Dampen it, then apply Estée Lauder Makeup Brush Cleanser to brush hair. Use your fingers to work into a lather. (In a pinch you can use baby shampoo or a mild cleanser.)
Rinse well, then blot excess water with a paper towel and reshape the brush.
Lay brush flat to dry. Place at edge of table or counter with bristles pointing out to air-dry completely. Avoid drying upright, which can cause bristles to spread and handles to crack.