MAC Cosmetics Brush Cleanser has become my staple brush cleanser. It cleans & conditions the brush fibers to make it last longer. MAC Cosmetics Brush Cleanser : This one product will clean, disinfect and condition the brush fibers so that brushes will last longer. It is convenient to use and is specifically designed to extend the life of high quality brushes. Brush Cleanser leaves your brushes smelling fresh and clean, and helps shorten their drying time.