Trust Michael on this!
A microwave can be very dangerous with volatile substances as it can "super heat" it - heat it above the vapor point. The result is that when you disturb it, it will flash. This can even happen with water. I have a friend who lost an eye when heating water in a microwave for tea. The microwave was at eye level and when he touched the cup, the water flashed to steam and burned his face, including his eye. If this had been beeswax, it would have flashed to flames.
In my opinion, a microwave is just too easy to misjudge for something like beeswax. And no amount of convenience is worth an eye, a face, or possibly even a house.
"Before I speak, I have something I'd like to say. . . . I will try to keep this short as long as I can." Yogi Berra