My customers frequently run into granulation issues. I tell them to eat the honey faster!
Most want to warm it up and tell me stories of stove-top warm water baths and microwaves. Lately I've been suggesting wrapping the jars up in a heating pad, the kind of pads you buy for achy joints and sore muscles. This seems to work fairly well and is still a pretty low heat source.
Any other ideas I can give my customers so they can warm their honey at home? None of them are willing to build a box with light bulbs.