A traditional method of dyeing carpet yarn in which loose skeins (loops) of already spun, plied yarn are immersed in dye baths before the yarn is knotted or woven into the rug. This technique, common in handmade carpets, works in separate batches, and small differences between batches, together with differences in the natural fat of the wool, produce the subtle color variations known as abrash that give traditional rugs their characteristic depth and visual interest. The process is still used by artisans who create custom-dyed yarns for specialty carpets.