Martha Stewart Living, July 2010
Sew handkerchief to a 14 1/2-inch-square piece of linen, using a small slip stitch.
Cut 2 pieces of linen for the back of the pillow, 9 1/2 by 14 1/2 inches. Hem one 9 1/2-inch edge of each piece, turning edge over 1/2 inch, then 1/2 inch again. Pin, and edge-stitch. Place handkerchief piece right side up; place linen pieces on top of handkerchief, right side down, aligning outside edges and overlapping at center to form a flap. Sew along edges of pillow with a 1/2-inch seam allowance. Turn pillowcase right side out, and press with an iron.
To make a flanged edge, topstitch a 1/2-inch border around edge of pillowcase. Insert pillow through back flap.
12-inch pillow insert
Backing a vintage hankie with linen makes it more durable as a pillowcase and lets you show off any illustrated borders or scalloped edges. The following instructions are for a standard 12-inch square handkerchief.