When people say bleach, most people think of the color white, Correct? White is often though of as a pure 또는 light color, and the shinigami clense the hollows 의해 slashing there masks, "purifiying" them in a way. the peoplw who created the 망가 wanted it to be white, but that didnt sound right to most of them
i heard because the creator was a 팬 of the american band Nervana and they had an album called Bleach 또는 something so he named his manga/anime after that.