How would you prewash yarn or thread?

To prewash yarn or thread, fill a basin with lukewarm water and add a gentle detergent suitable for delicate fabrics. Submerge the yarn or thread and gently agitate it to release any dirt or oils, being careful not to agitate too vigorously to avoid tangling. After 10-15 minutes, rinse thoroughly with cool water until the water runs clear, then lay the yarn flat to dry away from direct sunlight to prevent fading. This process helps remove any impurities and ensures the fibers are clean before use.