If you use mineral foundation or any other mineral makeup it is very important for you to clean your brushes at least once every week, you will also need to make sure that you clean your mineral makeup brushes the right way so they do not become misshapen or start to loose hair. If you apply your mineral foundation powder time after time with the same brush without ever washing it you are in danger of suffering from breakouts associated with bacterial build up and a dull looking skin.
You might not see it, but dead skin and oil builds up on your brushes each time you use them, oily old brushes will make your mineral foundation powder and other mineral powders look pasty.
The best brush for applying your mineral foundation is a kabuki brush, these brushes are made from sable hair, squirrel hair, goat hair etc. The dome shaped hairs in the brushes hold the minerals better for a more even application. The animals are groomed to get the hairs, this way there is usually no cruelty to the animal. Not all kabuki brushes are made from animal hair though; some are made from taklon and a few other synthetic materials, it is important to know the material from which your kabuki brush is made as this will help to determine the method to use when washing.
To wash your natural bristle mineral makeup brush, pour a little shampoo, hand wash soap or any antibacterial in a bowl and add some warm water. Then swirl the soap and water together before swirling your bristles in the soapy water, take care not to wet the handle or soak the handle. Keep swirling your bristles in the soapy water for about 2 minutes. Empty the bowl and add some warm clean water then swirl your bristles in the water for about a minute repeating the process and changing the water until it is devoid of bubbles (you need to make sure you use only a little soap in the first process or else you would find that it is soapier than you wanted and would need a lot more rinsing!). Shake off the excess water and lie flat on a clean surface (do not stand your brush on the handle when wet as water might loosen the glue holding the bristles in place).
If your brush is made from a synthetic material you will need to be careful when washing as they easily get misshapen, you will need to hold the bristles (lightly) with a rubber band before following the process above this will ensure the bristles keep their shape. Take off rubber band when dry.