answer 1
I use a daily spray brush cleaner for gels, but for powder sometimes I can just wipe it off on a towel. About every other week I'll clean all my brushes with Johnson's baby shampoo (MUA's highly recommend this!) and let them dry off the side of the sink so the water doesn't get into the base of the brush head. Hope this helps!
answer 2
I use baby shampoo on all of my brushes. I find it keeps them soft but cleans very well.
answer 3
I clean this brush either with Laura Mercier's brush cleaner, which I think is fabulous, or a tiny bit of hand soap. If I use the hand soap, I dampen the bristles, put a small bit of the soap in my palm, swish the bristles back and forth in it, then rinse. Simple!