WE have an old style freezer that has to be defrosted manually, and today was the day.  Standard procedure is to put some pans of hot water in to warm it up a little, then a hair dryer to melt/loosen the frost.  All went well until I got to the last part, and no matter how much I held the dryer directly on the tube (to the point that I was getting concerned about how hot the plastic might get), the last tube simply wouldn't melt.  I spent a good hour on the rest of eth freezer, and close to a half hour on the last part of the last shelf, and there is still ice on it.  What's happening?
The tube is the same size as the rest but ends in a very small tube that I assume is serving as a restrictor for the gas.