When I worked in teh anthropology department at a large natural history museum in the west we would do behind the scenes tours by advance appointment (with a museum admission upcharge) for adult groups only in just a couple of our storage rooms.  The curators had pre-selected the ones we would do -- ceramics storage and large stone artifacts, others, especially our NAGPRA storage, were strcitly off limits.  Generally we only did the tours in the afternoons so that in the morning we could put away what we were working on, tidy up, a pull out a couple of "show & tell" artifacts.   To ensure that the creeping hands would be adequately covered (you KNOW several people WILL touch) we issued every person white gloves that they had to wear for the duration of the tour. We collected them at the end and washed them before the next tour.  

I was just a grad student at the time, but gave the majority of the tours with a volunteer or our ethnology curator.  They were very popular and some groups, like Elderhostel, booked every year. 

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