wool-extract

from The Century Dictionary.

• noun Fabrics of mixed wool and cotton are steeped in dilute sulphuric or hydrochloric acid, dried, and heated to about 110°C., which ‘carbonizes’ the cotton and makes it easily reducible to powder: this powder is separated by dnsting and screening.
• noun Wool recovered from mixed fabrics of wool and cotton by subjecting them to a chemical process which destroys the cotton.