I have a small collection of historic photos, most bought via ebay. It dawned on me a couple of years back that I could put together my own small history of photography quite cheaply. I own a daguerreotype, tintype, some cartes de visite & a lot of glass negs. I always look at the image as this has to hold some interest for me apart from the medium. A few of the items I own are pornographic or erotic in some way. This genre is an important part of photography. People were making explicit dags only a few years after its invention.
I have seen this stuff being sold on ebay, I think you just have to be careful how it's presented. Show the image but black out any genitalia. Sell the neg & the print together. I would be interested in buying some but I'd have to see the imagery first.