Probably not quite vintage yet, this is a gently washed/faded Carhartt bandana handkerchief. It's dark blue with white diamonds & tools border, and a large C Carhartt logo in the center.
 
Pre-owned, washed and worn. In good condition but the blue has faded to a soft dark blue (my photo isn't very accurate... sorry!)
 
Measures 21" square
 
#392