I use shampoo... baby shampoo when I have it, regular if I don't. In between washings, I wipe them with Sephora makeup brush cleansing wipes. I have a brush cleanser, but I feel like my brushes get cleaner with shampoo (probably not true, but it makes me feel better )
Liquid hand soap...seriously, forevah. And I've never had a problem with any of the brushes, some of which I've also had forever. I just squeeze on some soap from the dispenser, wash the brush, rinse really well, and let them air dry.
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"Good taste shouldn't have to cost anything extra." - Mickey Drexler