Original: Dirt and sweat from a person's neck and wrists would stick to the starch rather than to the fibers of the clothing, and would easily wash away along with the starch.
Simplified: There are also different kinds of starch, like laundry starch, which gives clothing a smooth and crisp feel. Sweat and dirt from a personâ s wrist and neck will stick to the starch on the clothes, not to the fibers of the clothes, and will wash away along with the starch.