I would be very wary of melting cappings in a microwave.  It can be done but
I would use a low power level because if you heat too quickly the honey may
boil.  By boiling honey under a layer of molten wax you have the potential
of a very explosive mixture if you try stirring this with anything.
I have had this happen in a water bath where wax covered the water surface
and suffered a nasty burn.
 
You will also adulterate the honey by heating too hot.  It will caramelise
and give an off taste which renders the honey only suitable for cooking with
not selling or feeding to bees.   The wax also takes on a very brittle
texture and was not really suitable for turning into candles or blocks and
was really only suitable for incorporating into polish or trading into the
foundation manufacturers where it would be mixed with large quantities of
other wax.
 
We have in the past melted honey, in buckets, in the microwave but done this
slowly so that any wax melted with the honey and did not form a complete
layer on the top.
 
Barbara Dalby, England