In the case of the Philadelphia Commercial Museum, they just gave everything away.
The Philadelphia Commercial Museum was built in 1899 by a University of Pennsylvania botany professor named William Wilson. Wilson was inspired by the 1893 World's Fair in Chicago and hoped to create a type of permanent world's fair in the Commercial Museum. With this mandate the museum became the official repository for objects associated with the turn of the century world's fairs. It was a tourist destination and an educational resource for business students.
By the 1920's the US Department of Commerce was flourishing and formal business schools attached to universities had evolved. People also stopped caring about world's fairs (really, they're still happening and nobody cares). So the museum became pretty much irrelevant. The museum eventually closed and the objects of value were taken by local institutions and universities. The remained of the collection was stored by the City of Philadelphia in a warehouse. Until now, when the City decided to give them all away.
People at the Centre made a Thursday morning appointment: we were hoping to find paper, books, photos... things to experiment with, and possibly some cool random stuff as well. When we arrived, there were boxes and tissue paper all over, objects crushed and total chaos. There were thousands of baskets and other ethnographic things. I don't like ethnographic things very much.
Happily, we did find a box of interesting papers. An accompanying label identified it as joss paper or ghost money, faux paper money intended to be burnt for one's ancestors.
I think the dark irregular square shape in the center is silver leaf, but I don't have an XRF to back up this claim. Silver leaf oxidizes over time, turning black. Silver and gold leaf are both common to these types of papers.
This was a much larger sheet of paper, very brightly colored.
Detail of the pattern.
In the category of cool random things, everyone in the group found a few interesting things to keep for themselves (Val took a functional model of a stove). I picked up a strange wooden knife-thing that I intend to turn into a conservation tool. I also got two little pine boxes, probably shipping crates. I have no idea what they say: I'm thinking it is Chinese. Anyway, they are covered in filth (from old coal-fired furnaces and whatnot).
Both have little stickers on the back indicating that they passed through US Customs and were intended for the Panama Pacific International Exposition of 1915.