Thank you for mentioning this. I was aware of the related use test but had always imagined it would be satisfied in situations where a "Friends of" charity regularly raises money for an arts or other organization by selling donated collectibles at public auction. After reading up some more, it seems I was probably mistaken. Most of the examples of related use I find involve displaying the items in a museum or school. The unrelated use examples are all about the charity selling the donated items.
I feel there's still some ambiguity because I can't find any distinction made between a charity selling a donated item because they can't find a use for it (rare books donated to a pet shelter) and charities like Goodwill whose primary activity is soliciting and selling donated items.
