Estate Sale find: Seller's grandfather used to work in a Ballroom in NYC circa the 1930s into the 1940s.
He was a judge at many "dance till you drop" marathons.
Clever use (hack) of a safety pin on back and the tin frame of the button appears to be the same stamp/punch-die as a milk bottle cap ! ?
Signs of the depression era, I guess.
Unique - not many of these survived.
Shipping is $6.25