Your Fyber Kit may develop unwanted curls or straightened fibers. If that's the case, then you'll want to adjust how your end glow fiber optic product is stored. This is because end glow fibers will conform to the shape that they are stored. If you want more curls, then store the fibers curled. If you want straighter fibers, then hang the product from your closet door until the fibers straighten out. DO NOT expose them to temperatures that cause the plastic to melt. This will deform the fibers and cause them to bend. If you do want to use heat to manipulate the fibers, use the heat source on a small sample size of the product. If you like the effect, then you can apply it to the rest of the fibers. Melting or bending fibers is not reversible.