I use tubs with air holes in them. During shed times, I mist the inside of the entire tub and the substrate (paper towel.) I plug most of the holes with tape to retain humidity for shed times; normally, they are open and allow for ventilation. I always leave a few open though.
Misting the snake itself is ok, but I would do it fast, with warm-enough water; most of mine stress when being sprayed and I make it fast and only really do this if I am late in noticing a shed (like if I were out of town for a few days.)