Most makeup brands that are available with makeup brushes, like MAC and Shu Uemura, also carry brush-cleansers. But you can also use dishwashing liquid. Here is how: Get a clean cup and half-fill with water. Add about two drops of dishwashing liquid soap. Dunk the used brush in the water and twirl it around; you will see the makeup separating from the brush. Rinse the brush with tap water afterward, then place on top of a small towel to dry. It works!