I use scar makeup, which is as thick as stage makeup. Well, a lot of that inevitably ends up on my powder brush, and after a bit it needs to be cleaned. I've tried expensive brush cleaners and high-end shampoos, but nothing worked! Then I soaked my kabuki brush in apple cider vinegar for 48 hours and it is brand new and softer again. Try it.
Use Makeup Brushes To Clean Keyboards