I did this for 10 years at the Historical Museum where I used to work.. There were upwards of 30,000 to 50,000 artifacts. I would go througn and separate out the accessioned artifacts first and you may need to re-mark them archivally. They would be the fastest to get rid of. It depends on how your information is organized. We had physical cards as well as artifacts on a computer collections program. Go for the easiest to locate first or the stuff that seems easily recognizable. Your volunteers may have different abilities also. Some may be good for faster physical marking of the collections and others may be better at finding collections and donors (research). I would save the problem boxes for last, perhaps giving them a cursory look, and assigning someone to research the kind of collecton it is, or the donors to come up with a match. (of course that doesn’t always happen. I remember a collection of clothing that just said “trunk of old clothing” Try to figure that one out. A horror story happened when, one of the collections on long time loan (before my watch, we didn’t do that) was a local collection of spearheads and arrow points that was never marked and just thrown in with other unmarked, similar stone pieces. The son of the deceased donor wanted the collection back, and so the collections people at that time went through and said….Well, he had two of these and three of those” They were not id’d well enough on the accession cards. So, there you go. We all have those nightmares.