Hand-knitted items tend to curl at the edges, especially narrower, straight objects like scarves or sleeves. Sewing the seams together removes the rolled edges, but scarves are seldom more than one layer, so knitters can block the scarf, which permanently removes the curled or rolled edges. You can add a crocheted border to the scarf, although it's easy to correct the rolling edges simply by using steam to uncurl them.
Things You'll Need
Set up your ironing board and fill the iron with water. Select the steam setting at the lowest temperature.
Lay the scarf right side up on the ironing board. When the edges curl, they usually do so to the wrong side of the knitted object. By laying the right side up, you can force the curl to lay flat. If it's tightly curled, pin the scarf edges to the ironing board to lay the scarf flat.
Lay a cotton towel on top of the scarf's edges once the edges are flat.
Place the iron close to the surface of the towel, but not on it, and push the steam button to force the iron to produce steam. Laying the iron on top of the towel flattens the knitting permanently and may leave an undesirable mark. Continue the process of steaming until you have straightened the rolled edges of the scarf. Let the scarf cool before taking it off the ironing board. Remove any pins, and hang or fold the scarf.
Natural fibers block more easily than synthetics, which typically do not tolerate the heat of the iron as well as animal or plant fibers. Use extra care when blocking synthetic fibers. If you knit another scarf and want to avoid curled or rolled edges, knit the first and last few stitches of each row in garter stitch.