There are a vast amount of cleanser solutions or brush cleaners out there on the market and I have used many different ones over the years in every price bracket. To sterilize brushes keeps them hygienic.The hairs or bristles of the brushes need careful washing to get the maximum life out of them.Stale makeup in the form of Oils, Creams, Powders and Lotions are all mixed onto the bristles which must be washed off or will be transferred in your next application.