O.S.P. Minstrels
As remarkable as it seems, this professionally printed card is from a prison minstrel show-- i.e. O.S.P. seems to stand for "Old Salem Prison." (See attached newspaper article from 12/29/1915). This "Souvenir Card" (with non-postcard back) from "Jingling Johnson" and "Happy Gordon" featuring a performer in blackface and another as a hobo clown in a comic car labelled "Salem Jitney," has a date of December 30, 1915 and was probably issued as a holiday/New Year's card.