I use 1 to 1 1/2 inches of 85 degree water in a closed sterilite tub no holes.
I also place a hand towel in the bottom and if the shed is really bad I place a 1/2 log hid in the tub for the snake to sit on and rub against.
After 30 minutes I replenish with more 85 degree water and if the shed isn't off I do it again.
Two 30 minute soaks and almost any bad shed will slide right off.