When evaluating scoured wool, the most critical factors are fiber diameter (micron count), staple length, and yield. You must ensure the wool has undergone a professional scouring process to remove lanolin, suint, and vegetable matter (VM). High-quality scoured wool should have a residual grease content of less than 0.5% to 1.0% to ensure optimal performance in spinning or felting. Always request an IWTO (International Wool Textile Organization) test certificate to verify these technical specifications.