I used to work in a library, and one task we sometimes had to do was to check the book drop bin every morning, collect all the books, and put them on a cart to take upstairs to be checked in. One morning, I was scooping up books by the handful, as usual, when I realized that I had some sort of weird goopy stuff all over my hands. It was all over the books, the book drop, etc. I saw the bag of it, a large clear plastic bag leaking all over the place.
I'll mention that this was shortly after September 11th, 2001, and while all the anthrax scares were going on, with anthrax being sent to congressmen and such.
I was immediately sent to the bathroom to scrub, and somebody came to pick up the stuff and figure out what it was. I had to get back to work, but my hands got red and itchy where I'd touched the stuff. I have no allergies, zip, nada, zilch, so this was a disturbing sign.
What did it turn out to be? Hand soap. Concentrated hand soap. Somebody had stolen it out of a gas station's bathroom, just taken the entire tube insert thing out, then tossed it into the book drop as vandalism.
Apparently, hand soap is concentrated enough that if you get a whole lot of it all over your hands, and it takes you a few minutes to get to the bathroom to wash it off, it will irritate your skin. But that's all. Whew.
However, I would *never* have thought to wear gloves while looking in the book drop. And really I wouldn't have when looking through, say, a bag of donations intended for Goodwill, which is what I picture in the museum situation. I'm picturing miscellaneous trinkets and things of that sort. Of course, if containers still containing food, Rx bottles, and bottles of chemicals were sometimes appearing in donations, then maybe it would generally be a good idea with that particular donor!