The Maryland Historical Society, Baltimore (at least the last time I visited a
couple of years ago) sells/sold antiques through its museum shop.  As a
"museum professional" I was really taken aback when I saw the high percentage
of antique and collectable merchandise.  I thought it would send a very poor
message to the visitor/public (what are collections and what is merchandise?).
My understanding from speaking to a former MHS staffperson was that the shop
was stocked by a local antiques dealer and not from deaccessioned objects (and
was patronized by staffmember in question).  I am a long-standing supporter of
MHS and I do not wish this to be taken as negative or questioning their
ethical standards.  Just an observation as part of a free professional
discussion (i.e., please don't have me kneecapped in a Baltimore side street).
Different strokes...

With deaccessioned material I would tread very carefully as the AAM Ethics
Code is very specific (call AAM ethics advisor at 202-289-1818).  If your
board has decided to reevaluate the accessioned collection in light of a
revised, approved and adopted mission statement -- Great but they should
consider the intent of the original donors and/or earlier boardmembers who
accepted, purchased, etc., these soon to be discarded materials (are there
stipulations in the original terms of gift?  Should they ethically be offered
back to the donor or his/her legal heirs?).  The term "in perpetuity" lunges
to mind.  A more suitable method would be to transfer the items to a more
suitable museum collection and if no takers to run them through a public
auction house (preferably out of the region!).

Good luck.