The method I use to warm honey is to put the sealed jars of honey in the
dishwasher!  The top temperature is between 120 and 130 degrees F (as
measured on my brewing thermometer), all the crystals are melted, and
the jars come out squeaky clean to boot!
 
This method is not ideal for large batches and temperatures may vary
in dishwashers, but it fits my needs perfectly.  I don't recommend that
you buy a dishwasher for this purpose, but if you already have one....
 
Aaron Morris
Upstate New York Hobby Beekeeper
Vice President, Southern Adirondack Beekeepers' Association