Professional makeup artists should cleanse and disinfect brushes between every client to protect their clients from transmittable bacteria. Consumer users should also sanitize and disinfect their brushes on a regular basis, as often as once a week depending on your brush use. Every time you use a makeup brush you are sweeping it across your face and your makeup, and unless you have just disinfected your face and your makeup every single time you apply makeup, those brushes are accumulating bacteria. Always wash and disinfect your brushes after using them if you have a cold or a bacterial infection.
Wet your brush with warm water. Always keep the bristles pointing down so water does not go up into the glue or handle and cause deterioration of your brushes.
Dispense anti-bacterial soap into your hand and swirl the bristles of the brush in the soap. Use your fingers to gently massage the soap into the bristles up to the metal ferrule.
Rinse the brush with warm water and gently squeeze from the ferrule down to the ends of the hairs. If the water coming out of the hairs is discolored from makeup residue, wash again with soap and rinse. Repeat until the water runs clear.
Pat the brushes dry to remove any excess water.
Pour 99% alcohol, professional grade brush cleaner or an Environmental Protection Agency (EPA) registered disinfectant into a dish to a depth of about 1 inch. Most states recognize 99% alcohol as an adequate disinfectant. Many professional brush cleaners kill bacteria on contact. If you aren't sure about yours or want to buy one, visit a local beauty supply store. There are also EPA-registered disinfectants that are recognized as bactericidal, fungicidal and tuberculocidal which will kill almost everything that could be on your brushes. Alcohol and EPA disinfectants will not have any conditioning agents for the benefit of your brushes and could cause your brushes to become dry and stiff with repeated use, so it is best to reserve these for when you are sure it is necessary and stick to a proper brush cleaner with disinfectant properties for routine brush cleaning.
Dip the brush hairs into the disinfectant of your choice to halfway up the hairs. The hairs will wick some of the disinfectant up their length, so do not dip all the way to the ferrule.
Swirl the brush on a small towel gently, so as to disturb the brush fibers as little as possible while still removing any residue.
Dip the brush fibers into the disinfectant halfway one more time.
Reshape the fibers and lay the brushes on a clean towel to dry. Always dry brushes on their sides rather than upright in a cup. Preventing the contact of moisture with the glue inside the ferrule is imperative to maximizing the lifespan of your brushes.