I let my beauty blender sit in hot water with antibac soap and Fairy liquid. After that, squish it a lot to work the soap in, leave it 15 minutes, and then rinse. Sometimes I’ll toss it in the washer in a sock with towels if I’m doing a hot wash.
With brushes, I first rinse in hot soapy water, then use Fairy on a brush mat or just with fingers to work it through. Leave for 10 minutes.