I had to do this to a nasty one a couple weeks ago.  I went out
before daybreak, sealed the entrance, and put some PDB (para-moth)
crystals on a double screen board which I put over the inner cover.
I taped a plastic bag over the double screen to seal it and taped the
joints between the hive bodies.  I believe they were dead within 24
hours but I left it alone for about 4 days before cleaning it out.
 
In the process of cleaning & inspecting I noticed what I assumed
were dead wax moth larva at a couple of locations on the brood comb.
They had made about 1 inch tracks before succumbing to the PDB fumes.
 I presume that wax moth eggs are usually present and the bees take
care of the larva when they hatch.  In this case the bees were dead
or dying which allowed the larva to survive for a short time before
the PDB took care of them.
 
Rod
Rod Rupert
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