Like I mentioned on Facebook, I have a 55 gallon fish tank and a 40 gallon snapping turtle tank in the room that keep humidity at 45-60% year round. I don't use the tub-and-rack systems that many do, I like to be able to see my snakes so I keep them in well ventilated glass and/or acrylic cages. Smaller ones are housed in ten gallons with mesh tops on them.
I use paper as a substrate and for higher humidity areas I add two Sterilite hide boxes stacked over the heating source so one is warmer and one is cooler. The boxes are half filled with damp sphagnum moss and 90% of the time the snakes deposit their stools and urates in the hide boxes, which makes cleaning a lot easier.
I don't soak them at all, other than those that can fit into their water dishes. I will spray them off in their feeding tubs and wipe them down if they have feces, urates or blood (from a rodent) on them.