You can dampen it in water and then use towel to remove excess and leave to dry as simple as that /emoticons/[email protected] 2x" width="20" height="20" />
It washes just like any other beauty sponge. I like using Mona Lisa's Pink Soap (available at some craft stores like Michael's) as well as Koren's Soap.
I use the BeautyCleanser Solid by BeautyBlender on it, and it gets everything out of it. In fact, I use this soap just for cleaning all of my makeup sponges.