Sheep fleece is often marred by thorns, seeds, burrs and other vegetative matter that must be cleaned out before the wool can be used. Traditional methods of combing or using acids to remove the debris can damage the fiber or result in a substantial loss of wool.Researchers at A.N. Kosygin Moscow State Textile University have come up with a very promising cleaning technique. After washing the fleece to remove sweat, grease and mud, they irradiate it with short pulses from powerful 20-kW lamps. The scientists, who have been working on wool-refining solutions for more than 20 years, previously tried lasers for irradiation but recently switched to ordinary lamps, whose light is filtered to remove potentially destructive ultraviolet and infrared radiation. The light heats the dark foreign matter until it turns to ash and can be shaken out of the fleece. The method does not damage the wool; in fact, it actually improves it because the surface becomes smoother, the core more elastic and flexible, and the color snowy white. Yarn from the treated wool is more durable and holds dye better, the researchers report.The team is investigating technologies to exploit its discovery with the hope of turning a “thorny” processing problem into a “shear” delight.