Cut off the sleeves and neckline, forming a curve from the armpit area to the center of the neck.
Unfold the shirt. It should be rounded where the sleeves and neckline were removed.
Flip the shirt inside out and sew across the cut curved area.
Flip the shirt right side out again, and make 4 slits in the hem enclosure (only through the top layer of fabric). Make one on either side of the seams on each side of the shirt. (If your shirt didn't have seams, make 2 slits about an inch apart on either side of the hem.)
Pin a safety pin to one end of a ribbon or cord. Use the safety pin to help guide the ribbon through the hem enclosure of the t-shirt.You want to go in on one side on the front of the shirt, through the hem and out on the opposite side. Then, go back through the nearby hole on the back of the shirt, through the hem on the back, and come out on the opposite side.
Leaving enough ribbon or cording to easily open the bag and cut off any excess. Tie the cut ends together.
Make the Fabric Stamps
Decide what you want to stamp on your bag. Draw out the shapes on craft foam and cut them out.
Glue the craft foam shapes onto a clear, hard plastic. (I've used broken cd cases and other plastic scraps.)
Decorate the bag
Dab some fabric paint onto your homemade fabric stamp and stamp onto the fabric.
To make the jack-o'-lantern mouth, stamp a W-shaped stamp 3 times, overlapping the edges. (See how it's a bit darker where it overlapped in the picture.)We used a triangle for the eyes.
The fabric stamps can be glued onto any hard surface, but clear plastic makes it easier to see where you are stamping. (Plastic from old CD cases makes a great backing material.)
When stamping on the fabric, it's a good idea to insert a piece of cardboard in the bag to keep the paint from seeping through to the other side.
To set the paint, follow the directions for your particular paint. Normally, though, you should cover the dry paint with parchment paper and iron the design for around a minute.
Recipe printed from Oh, The Things We'll Make! Blog. https://thethingswellmake.com/make-a-trick-or-treat-bag-t-shirt-upcycle-one-seam/