If your brushes are natural (sable, mink, etc), baby shampoo is the best product for cleaning because it is pH balance and won't strip the natural oils from the bristles. A good conditioning treatment for natural brushes should be used periodically to restore oils lost over time. Washing is recommended weekly for best care (daily cleaning is likely to strip them, making the strands porous and apt to absorb product in spots, creating splotchy application). Synthetic brushes can be cleaned daily because they have no natural oils; however, a conditioning agent is recommended or they will split and break with frequent washing. An antibacterial spray cleaner is great to keep on hand for between-cleaning touchups - just spray on a tissue and blot the brush. It is amazing how much residue will come off the brush, reducing the need for too-frequent cleaning which really damages brushes. One thing good to remember when cleaning any brush is not to get the ferrule wet - only allow the exposed part of the hairs to be in water because water causes damage to the wood inside the ferrule, causing it to expand and shrink then releasing hairs once that happens. In short, your brush goes bald! Or at least severely thin.
