Gently swirl your brush around in the cleanser for about 30 seconds or so.Squeeze a quarter size amount of baby shampoo or brush cleanser into the palm of your hand.Make sure to ALWAYS keep your brushes facing downward! That way water doesn’t get into the brush itself and loosen the glue holding the bristles in place!
You can either use a cleanser specifically made for cleaning brushes, like this one or this one– or, like me, you can use baby shampoo! (I have a lot of it on hand, nowadays!) Basically you want something very gentle, but still cleansing. There are two really great ways to go about this, but they all have the same techniques.