I have noted previously the best way to store supers, but since the
topic is current again, let me emphasize a key principle:
 
Wax moths will not enter clean dry supers,  since in them there is
nothing for the larvae to eat.
 
Therefore, 1) Avoid storing wet supers.  Have the bees clean them out
before storage.
2) Avoid storing supers with pollen and larval cocoons.  The best way to
do this is to always use a queen excluder to keep the queen completely
out of the supers, never letting her lay in them at all.  The supers
should be for surplus honey storage only, the brood nest for brood
rearing.  If the queen gets through an excluder (which happens), throw
it away: it is no good.
 
I have stored supers for 20 years, covered always, both out of doors and
in a closed shed.  I never have stored them over PDB crystals.  In all
this time, I have never had wax moth destruction of this comb, despite
having had stored brood combs totally devastated by moths.  Now,
occasionally a few moth larvae will find isolated pollen cells and get
into them, but this is always very limited and easy to fix.
 
Ted Fischer
Dexter, Michigan USA