Popular from about 1904 to 1909, leather post cards were a popular novelty item. The United States Postal Service banned leather post cards in 1909, due to the leather causing jams in the equipment at the Post Office. Pictured below are three leather post cards from the historical collections of the Sandusky Library Archives Research Center.
The Erie County Courthouse is featured in this post card.
This comical post card appears to have been painted, with the location of Sandusky burned into the leather.