With the mantra "reduce, reuse, recycle" on everyone's mind, reusing an old sweater by recycling it into wool dryer balls will reduce the need to buy tumble dryer sheets. With old sweaters lying around, there's no need to shell out on new wool for this project. Use an adult-sized large sweater to make at least three wool tumber dryer balls from one sweater.
Lay out the clean and dry sweater on a flat surface. Cut a 7.5 cm (3 inch) square out of one layer of the sweater.
Ball up the square in your hand, pressing it as tightly together as you can. Wrap a scrap of wool yarn around the ball at least 10 times. Secure the end by tying or pulling through the ball using the crochet hook. The square should remain in a ball after cycling through the washing machine. Wrap it with more yarn if you feel it is needed to stay secure.
Place the sweater ball into the leg of an old pair of tights, and tie a knot in the tights to secure the sweater ball. Cut off the excess nylon.
Set the washing machine on hot, and run the sweater ball through an entire wash cycle. Remove from the washing machine, and run through the tumble dryer for a complete cycle. Remove from the dryer.
Remove the sweater ball from the leg of the tights. It should have started to felt. When it is properly felted, you will not be able to see the individual crochet or knitted stitches in the sweater ball. It will look very similar to a piece of felt you buy from a shop.
Cut a 17.5 cm (7 inch) square out of a single layer of the sweater. Wrap the square around the felted ball. Secure by wrapping with the yarn scraps again, and secure the end by tying or pulling through the felted ball with the crochet hook.
Cut an 27.5 cm (11 inch) square out of a single layer of the sweater if you prefer a bigger wool dryer ball. Wrap the square around the felted ball, and secure by wrapping with the yarn scraps. Secure the end by tying or pulling through the felted ball with the crochet hook.
These balls will felt every time they are used in the dryer, so it is OK if they are not completely felted when you are finished.
You can also put a small sachet of herbs inside the first ball to scent your clothes. Once the smell wears off, there is no way to replace the sachet.