Wool Slubs, Knopps, Knepps and Burrs are waste products of industrial fibre processing and yarn spinning. These are formed when fibres catch in the machinery and roll back onto themselves forming little pod, or ball shapes.
They can also be produced if the animal's fleece becomes entangled on itself whilst still on the animal.
Wool Slubs,Knopps, Knepps and Burrs are great for adding character to yarn by being introduced to the carded or combed sliver before spinning. They can also add texture to felt by sprinkling either between the layers or on top before you begin wet felting. They can even be added your papermaking, by adding in between layers of your base fibres.
I hope this helps?
Have a wonderful day... Sara x