If I were an exhibitor, which I’m not, an artistic exhibit on Spanish American War patriotic revenue usages would make for a lovely visual presentation.
The tough thing would be coming up with enough different examples to comprise an exhibit. I’ve kept an eye out for the last 10 years and have only managed to acquire 3 examples, the last of which just arrived this week:
Patriotic stationery used for a banking transaction.
My other examples:
Illegal usage of R155 as postage on a Spanish American War patriotic cover.
1-Cent battleship on a patriotic cover, not illegally used as postage, as I believe the international rate was 10 cents. Rather, I believe it was used as a patriotic label/cinderella, i.e., “Remember the Maine!”.