Optical lighteners ndi mankhwala opangidwa omwe amawonjezedwa ku ufa wamadzimadzi ndi detergent kuti zovala ziwoneke zoyera, zowala komanso zoyera.Ndiwo m'malo amakono a njira yakale yopangira bluing ndikuwonjezera utoto wochepa wa buluu pansalu kuti iwoneke yoyera.