How can you tell if a jumper is made of wool or not if the labels are missing?

To determine if a jumper is made of wool without labels, you can perform a few tests. First, feel the texture; wool is generally soft and elastic, while synthetic fibers may feel slick or overly smooth. Additionally, you can conduct a burn test by taking a small fiber and burning it; wool will smell like burnt hair and produce ash, while synthetic fibers will melt and smell like plastic. Lastly, if you stretch the fabric, wool tends to return to its original shape due to its natural elasticity.