Baste 1/2" from all four raw edges in contrasting thread.
Press four corners diagonally, meeting basting lines on both sides.
Trim the tips of the pressed corners diagonally from one side to the other, removing a small triangle of fabric.
Turn under 1/4" so the raw edge hits just below the 1/2" basting line.
Turn under once again along the basting line. The corners are mitered and ready to hand baste in place until the narrow hem has been topstitched.
Finished bandana narrow hem with mitered corners.