A wool or hand-knotted rug is often the most valuable textile in a house. It's also the one most likely to be damaged by well-intentioned cleaning, because the methods that work beautifully on wall-to-wall synthetic carpet can do real harm to wool. The difference comes down to what the fiber is and how the rug was made. Wool Behaves Differently Than Synthetic Fiber Wool is a protein fiber, chemically closer to hair than to the nylon or polyester in most modern carpet. That ha