Cashmere sweaters are soft, warm and, unfortunately, expensive. If you are lucky enough to own your own little piece of cashmere heaven, you have probably grown attached to it. So if you have spotted a hole, you know throwing out the sweater is not an option. This mending method should save your cashmere sweater from the trash heap. It does not require any previous knitting experience or knowledge, but it does require patience and concentration.
Take your sweater with you to the yarn store so you can match the yarn as closely as possible. Look for yarn that most closely matches the colour and thickness, or "weight" of the yarn in your sweater. You don't have to use cashmere yarn for mending.
Find the hole, or "open stitches." Lay the sweater on a flat surface. Do not pull on the fabric; pulling could make the hole bigger.
Place a safety pin through each open stitch along the top of the hole. Place additional safety pins through each open stitch along the bottom of the hole. Close the safety pins to secure the stitches while you mend.
Thread the embroidery needle: Place one end of yarn through the eye of the embroidery needle. Cut the yarn, leaving a tail at least 12 inches long. Do not knot the tail, and do not double the yarn as you would with thread.
Slip the tip of the embroidery needle through the closed stitch just to the left of the top row of open stitches. Pull the yarn through, leaving a tail about 1 inch long on the inside of the sweater. Tie a knot around the closed stitch with the tail of the mending yarn on the inside of the sweater.
Slip the embroidery needle through the first open stitch on the bottom row (the stitch farthest to the left) and pull the yarn through. Slip the embroidery needle through the top stitch just above that stitch and pull through. Repeat with each set of open top and bottom stitches until you have woven the yarn through each open stitch.
Slip the embroidery needle through the stitch just to the left of the once open stitches. Tie a knot around that stitch inside the sweater. Cut off any excess yarn.
Purchase your yarn from a yarn store rather than a big box craft store. The staff should be more knowledgeable and capable of helping you find the best matching yarn.
Unless you kept the extra swatch of yarn that may have come with your sweater, do not expect to find an exact match.