As experienced knitters will know, wool can be used in a vast range of ways, not just for Christmas jumpers. If you have some wool yarn left over from your latest project, then you can even use up the excess by making your own dryer balls. These in turn allow you to improve the effectiveness of a tumble dryer cycle.
Equipment
The most important part of making your dryer ball is using yarn made of pure wool, not cotton or synthetics. Perhaps you acquired a knitting kit from somewhere like www.woolcouturecompany.com/collections/knitting-kits, and once you finished making your scarf or blanket, you had some leftover yarn that you wanted to put to good use. You will also need a tube of fabric, something like a sock, to hold the yarn through the process.
Process
You need to wind your yarn up tightly, until you have a ball with a diameter of around 3-3.5 inches/7-9 centimetres. Make sure the end of the yarn is tucked in securely.
Now it is time to place it in your sock or equivalent, knotting the fabric to keep it safely enclosed. It will take three to four cycles through the washing machine at its highest temperature (add to a load of towels for better energy efficiency) to felt the balls so they are unlikely to unwind.
Extras
Add textures and patterns to your ball with different swatches before throwing it in the washing machine. You can also use essential oils for scented balls, though only in the safe and recommended way, including by diluting them.
Making dryer balls from scrap wool is not a complicated process and it is very useful in the practical sense. You could keep some for yourself or share some with friends as a gift.