Bleach Powder + Hot Water Stain Removal

Do you mean if your hair is stained from hair dyes?

I've just recently used bleach powder and hot water to help fade some unwanted colour that a toner seemed to leave behind, and it was an effective and non-damaging method by simply putting bleach powder into an application bottle, adding warm water, shaking well, applying to my hair, and leaving it on for a few minutes before rinsing it off.  Again, that was purely to remove some left-behind residue from toning.

Although my hair is slightly stained in the lengths from darker dyes I've used in the past, and unless you plan to re-dye over it in a darker colour, I've come to the conclusion that real hair stains can't be concealed or removed.  I gave up a few months ago after one last attempt at bleach and peroxide, with a bit of heat on those areas, and when I saw it came out no lighter than when I started, I realised it was stained for good!

It's really not noticeable though, and I've also learnt that you usually notice your own hair stains much more than anyone else would unless you point them out.  So I'm not convinced that bleach powder and hot water alone would do much for staining, but it is worth a try!

If the mix is left on for a longer time, or if this method is used repeatedly, it will cause damage. It is relatively non-damaging as long as the mix is only left on briefly, but I repeatedly put bleach and water on a strand test of already bleached hair with red staining, and after having the mix on for about an hour in total (which was several applications/rinses) it was pretty fried. (Not complete mush, but the condition had definitely deteriorated, it was fragile and easily broken) Also it didn't get much lighter after the first 5 minutes, so there is no advantage to leaving it on for longer.
So think of it as a mild bleach bath in terms of damage, only leave the mix on for 5-10 minutes to avoid damage, and deep condition afterwards.

That's helpful advice, Wicked Pixie... good to keep in mind it isn't necessarily "non-damaging"!

Thanks so much pixie! You're such a hair genius