There are myriad, appropriate brands available to purchase wherever you normally get shampoo. Just make sure the clarifying shampoo you select is non-color safe.
When possible, it’s advised that you wait a few days to allow your hair time to recuperate from the chemical processes used to dye it before attempting to scrub out the dye. If it has to come out as soon as possible, though, ensure you offset the damage as much as possible with conditioning.
You might want to bump the baking soda up to 3 cups if you have longer than shoulder-length hair.
Take care not to get the mixture in your eyes! You might want to use a towel or cloth around your head, to keep the mixture from dripping down toward your face.
After you’ve finished, avoid any styling that uses heat for a day or two. Both dyeing and “un”dyeing your hair take a toll.
You can get developer at a beauty store, drug store, or wherever you purchased your hair dye.
If you don’t have a shower cap, you can also cover your hair with plastic wrap.
Moisturize thoroughly with conditioner if your hair feels dry after you’ve washed the paste out.
Peroxide is definitely the least predictable, and likely the least optimal option available to you. It doesn’t work against the dye and chemicals already in your hair, but instead adds another one. Use it with caution.
Peroxide is safe to get on your skin, but can cause burning in your eyes. If you get some in them, flush them with cool water. Going outside in the sun can cause further lightening, but can also dry your hair out. Be aware of the effect sunlight will have if you choose to go outside with the peroxide in your hair. Use pins or clips to arrange your hair, so that you only spray the hair you want to.
A deep conditioning is recommended if your hair feels dry after the peroxide treatment.
