Detergent and bleach are made from different ingredients, ROSY LILY shoe shampoo is a detergent for cleaning, not bleaching. "Detergent" and "bleach" are fundamentally different, and detergent does not function to bleach.
"Detergent" is not used to whiten fabric. In other words,it is not possible to whiten yellowish shoes.It works to remove stains. On the other hand, "bleach" is a very strong chemical and it should be rinsed thoroughly with water after use.
In addition to changes in the color tone of the material itself, color change also happen when microscopic inorganic stain gets into the material. To put it simple, if fine stains such as sand get into the fabric, the material looks darker ( as inorganic stains). This is a type "irremovable" stain.
Another example is it's very difficult to remove cosmetic foundation when it gets on a shirt. Yet, although it looks dark in color, the stain can be removed when we wash the shirt, then it's clean. Detergent with optical brighteners is needed for this cleaning process.
Fluorescent whitening agents absorb ultraviolet rays and produce blue light. This is why they appear as white substances to human eyes even when they are actually discolored. However, this only works on a few materials, such as cotton, linen, rayon, and other materials with dark or pastel colors. ROSY LILY contains no optical brighteners for the above reason.
All in all, it is not possible to provide a detergent that will work universally for all materials for a variety of reasons.
