While we here at the Smart Aleck's Guide were working on our guide to grave robbing, we went looking for accounts of actual unwrapping parties. As far as we can tell, the term "unwrapping party" didn't appear in print until the very late 20th century. We never found a single account of anyone unwrapping a mummy for the fun of it at a social function. There are no diary entries like:
Today was the big unwrapping party of Lord Autumnbottom's estate...the creature was gruesome and the smell horrid, and Henry and I were so covered with yellow dust that a man outdoors thought we were urchins and suggested that we die and decrease the surplus population. Henry says we must get a mummy of our own before Ascot, but I'm not at all sure I shouldn't rather simply play whist.
Public unwrappings DID happen. Here's the "party" invitation that probably sparked the urban legend - it's advertised a gathering at Lord Londesborough's home with "a mummy from Thebes to be unrolled at half-past two:"
But while this sure looks like a party invite, it wasn't a social gathering. Surviving accounts of what went on that 10th day of June, 1850, make it sound less like a party than an academic lecture. Most attendees were members of the Society of Antiquaries.
There were many other notable unwrapping (including a highly-publicized one in Boston at which a man unwrapped a "princess" who turned out to have a wiener), but most of them were held in lecture halls and universities, not at private homes. Many accounts indicate that having one at a party would have stunk up the house (even by Victorian standards), and that the dust and dried bitumen would have gotten all over everyone's clothes. Unwrappings were not something to attend in party clothes!
Full details of what we "uncovered*" are in our new book, The Smart Aleck's Guide to Grave Robbing!
* - Yeah, when you talk about researching grave robbing, making puns about stories you "dug up" just comes with the territory.