Hello friends:

I am preparing an iron stain via Mallory's Iron stain method, which is basically similar to the Perl's Prussian blue for ferric iron.  Both stains require ferrocyanide to be mixed with a small percentage of hydrochloric acid--a mixture which brings about a toxic reaction liberating hydrogen cyaonide, nitrogen oxides and others. . . Have you guys just mixed this under the hood and done all of your work there, and then, how do you dispose of this beautiful mixture of black death? 
Thanks for your help,
Jon Kerr
Chief histologist,
Reference Pathology Services,
Sandy, Utah
"Liberty is the only thing you cannot have unless you 
   are willing to give it to others." 
   -William Allen White