Why do colored sponges not stain when they come into contact with bleach but almost anything else does?

Question

Why do colored sponges not stain when they come into contact with bleach but almost anything else does?

Answer 1

yes

Answer 2

Because sponges are not died they are the color they are to begin with.

Answer 3

I think sponges, like many plastic products, actually have the color impregnated into the plastic matrix and so you can't really get the color out without destroying the plastic (you can bleach it over time with UV rays that penetrate the plastic).  Other materials with "through body color" won't bleach either.  Also most mineral pigments won't bleach because they are usually oxidized metals.  That's why rocks and such don't bleach.  Most stuff that bleaches is organic dye based, which is made from large carbon-backbone molecules with reduced double bond "conjugated" (alternating double-single bonds that forms a giant "pi bond" structure that can interact with visible light) structures that can be oxidized easily.  Bleach is just a really powerful oxidizer.  Most things that bleach well are inherently white materials, such as cotton or paper or synthetic fabrics that have organic dyes bonded to their surface for color.  The bleach just gets at the surface, and kills the dyes.  

See, organic dyes bond well to the surface of things but they can be bleached.  Pigments, which cannot be bleached, don't bond as well to surfaces of materials and are not used for dying things, they have to be mixed into the material to be colored.  Pigments are usually mineral powders.

Plastics and rocks and glass and such things have the color impregnated throughout and the bleach cannot get inside, and even if it could, many of the colors are pigments that cannot be bleached.  Plastics may use pigments or organic dyes, but the bleach can't get inside the plastic.

Answer 4

Good question! Hope you get an answer because now I'm curious.