- 1). Machine wash and dry your cotton fabric. Iron the fabric straight out of the dryer before wrinkles or creases have time to set.
- 2). Measure and cut two 14-inch squares from both the shower curtain liner and cotton fabric.
- 3). Place out of the liner squares on your work surface; it doesn't matter which side faces up. Place the zipper right side up on top of the liner with one of the edges of the zipper tape lined up with one edge of the liner. Place one of the fabric squares on top with the wrong side facing up. Pin together the three materials along the edge with the zipper.
- 4). Install the zipper foot on your machine. Consult your machine's manual for instructions on how to do this--steps vary based on make and model. Sew the three materials together as close to the zipper as you can on the side of the zipper closest to the edge.
- 5). Flip both materials over the seam so the wrong side of the fabric is against the liner. Sew along the same side of the zipper, again 1/8 inch from the zipper. Repeat with the other two pieces of liner and fabric on the other side of the zipper.
- 6). Reset the presser foot on your machine. Bring the right sides of the fabric together, and the two pieces of liner together. You will end up with a large rectangle, half liner, half fabric with the zipper in the middle. Sew around the entire piece with a 1/4-inch seam allowance. Leave a 6-inch opening in the middle of the fabric's edge opposite the zipper.
- 7). Turn the wetbag right side out through the 6-inch opening. Fold 1/4-inch of the raw edges of the fabric in along the 6-inch opening, and slip stitch them closed with needle and thread to complete the bag.