Yarn can be spun from a variety of animal, plant and man-made fibres. If you purchase yarn that does not have its contents clearly labelled or unravel old sweaters to reuse the yarn, it can be difficult to know which fibre it is made from. Wool and acrylic yarns are especially hard to tell apart due to their similar texture and appearance. However, these two quick tests will reveal a yarn's true identity.
Light a match.
Hold the match to the end of the yarn to singe it. Wool will be slow to ignite and give a distinct odour of burnt hair. Acrylic, which is made of petroleum, will burn readily and quickly, and the yarn end will appear melted.
Extinguish the yarn completely by dunking it into a bowl of water.
Place the second sample of yarn into an old plastic container.
Cover with bleach and set aside, away from children and pets, as well as in an area that receives adequate ventilation.
Place on latex or rubber gloves to check the sample. If the sample appears to be dissolving or the fibres are being destroyed by the bleach, then the fibre is probably made of an animal fibre such as wool. If the yarn has lost its colouring but is otherwise undamaged, the yarn is likely made from acrylic.
Dispose of the bleach and yarn samples carefully.