I never soak my BPs, since it isn't a natural thing for them to do in the wild. I can guarantee that the damp pillowcase, with a washrag or small damp towel thrown in with the snake, will take care of the problem in no time.

I've always been one to take care of stuck sheds first thing as soon as I notice it. It's easy enough to get a pillowcase wet and throw them inside it and then back in their tub/cage for an hour or so. When you take them out, if the shed isn't gone it will be very easy to remove.