It is best for your brush if you clean it once a week. That way it will last longer, and it also helps tominimise bacteria. Clean your brush with intimate wash or a mild, fragrance-free shampoo.
Remember, water can dissolve glue, so when caring for your brush, it is important to keep water away from the glue and the handle when washing the brush. Let it dry on a clean, dry towel so that water does not run into the glued joint.