> we used to call old women blue-hairs. older women got gray hair or sometimes their blond hair yellowed. a technique for keeping white clothes bright and white at the time was to use a small amount of a bluing agent to the wash rinse cycle. these women reasoned that using the same bluing agent to their hair care process would brighten their dull, yellowing hair. used sparingly, it was somewhat effective but in most cases they though if a little worked well, a lot would be better.  instead, it just made their hair bluish. > laundry bluing is a product used to enhance the whiteness of fabrics by adding a small amount of blue dye, which counteracts yellowing. it is typically available in liquid or powdered form and is added during the washing process to make white clothes appear brighter.
United States