Make sure your scrap material is at least three times the length of the hair tie when cut into one long line.
Any hair tie will do, but try and use one that is really stretchy, and also the thicker the better.
Start by cutting your fabric into a slim rectangular shape. The longer the better, as you can always come back and cut it shorter if it ends up being too much lengthwise. The width of your material really depends on personal choice, I chose to have mine 7 cm, but you can have it bigger or smaller depending on how puffy you want your scrunchie to be. (The wider the width is, the bigger teh scrunchie becomes.)
NOTE: Don't forget that you are going to sew the two sides together, so it will become a little smaller. If you don't want that, add a little extra length on.
Next fold the material in half and make sure it is straight on both sides.
Take the material to the sewing machine and sew together, creating a long cylinder shape. Turn it inside out so that you can't see the stitching.
Cut your hair tie in half and pin a safety pin through one side. Using the safety pin as a guide, thread the hair tie through the material. When it gets the whole way through, hand stitch both sides of the hair tie back together.
Another scruchie we made today, except this one was a little smaller width wise, making the ruffles smaller.