Doug,
Won't freezing take care of the mites?  I think so - but I wonder what
others will say.
If no foul brood is present the bees should clean up the equipment admirably.
A local commercial beekeeper blasts suspicious equipment with a pressure
cleaner hot enough to soften the wax, etc. and not even 160F to cook the
microbe and spores.  He believably claims never to have problems with the
used equipment he buys after blasting the few offensive pieces.   This guy
buys up lots of 100's of hives and says that the bees will do a lot to clean
frames and hives themselves.
The local states collaborated with a program to treat hives a number of
years ago with ethylene but I guess it proved to be not cost effective.
Ditto with CO2, I think it was tricky to maintain the concentrations long
enough to kill off the pores of AFB.
Go for it. They're assembled and primed.
 
On Tue, 25 Jun 1996, Doug Robertson wrote:
 
> I have a chance to buy a couple of used hives from a someone.  They both
> succumbed last winter.  My wife is afraid of spreading any infestation to
> our new colony.  How can the used equipment be treated to kill any mites or
> other diseases?
>