I recently got a straight stem Peterson series of "Dracula" pipes. It has an colorful, acrylic stem, but the thing is stuck on the pipe like it was bolted on. How do I safely remove the stem from the bowl without ruining it? I've even considered using Liquid Wrench, but I'm afraid of what kind of effect that will have on the pipe. Is there a safe lubricating oil I can use, or does the refrigerator trick work? Thanks for reading!