To clean my makeup brushes without any harsh chemicals I use Dr. Bronner's unscented baby-mild pure liquid castile soap which basically consists of a combination of organic based oils. I pour some of the soap onto the brush while running the brush under the faucet and swirl the brush in circular motions against the palm of my hand (you can use a bowl if you prefer) and I repeat this process until the brush is clean of makeup residue. I then rinse the brush in a circular motion under warm/hot water, repeating until all the bristles on the brush is free of any soap. I then dry the brush in a circular motion on a clean dry towel until the bristles are mostly dry. Next I stuff a paper towel into the base of a drinking glass and store the clean brushes upside down in the glass. Then I leave the brushes to dry overnight so that any excess water gets drawn out of the ferule and onto the paper towel (if you have brush guards you can use those to help keep the form of the bristles while the brush dries). If the brush is still wet in the morning than blow some heat on it with a hairdryer for a minute or so, and avoid heating the ferule.