The obvious way to clean a hair brush is to remove the trapped hair from the bristles. To do this quickly, use a comb to cover more area on the brush and gather more strands at a time. Once the hair is out, you might notice some build-up at the base of the bristles. This is leftover hair styling gunk, oil and grease. Using an old toothbrush, gently scrub your brushes, combs and picks with warm water and a dab of shampoo until all of the build-up has been lifted from the base and bristles.