Do not wash Hengyuanxiang 100 pure wool hats. According to relevant public information, do not wash wool hats because the wool will shrink. If the hat is stained with dust or pet hair, you can use wide-surface tape, fold it over your finger to apply it, or choose a soft-bristled toothbrush to remove surface dust. Hengyuanxiang was founded by Shen Laizhou in Shanghai in 1927. Hengyuanxiang is currently the world's largest yarn manufacturer. In 2009, Hengyuanxiang was selected as the world's largest yarn manufacturer by the China World Records Association. Involving the three major industrial sectors of home textiles, knitting, and apparel, it is a comprehensive textile group company with hundreds of alliance factories, more than 4,000 distribution outlets, and more than 2,000 specifications and varieties.