In the last analysis though, the stuck seatpost or stem are as bad as it gets for frozen parts on a bicycle. Ask any mechanic. If after trying all of these methods, and the critter is still not going to budge, it becomes time to get truly inventive (if not diabolical) - such as using an air-compressor to blow the thing out, or chaining the bike to a tree and hooking the thing to an electric-winch mounted on your truck! Many bizarre ways have been tried. Some have succeeded. Some resulted in disaster!
Have a blast!