I bought a box bleach kit and divided it in half, since my hair is fine and I don't really need a full box.
But I realized I put the powder in a regular ziplock bag, and after a quick internet search all I could come up with was information about bleach to clean, not bleach for hair. But it said that bleach is light sensitive.
So if I use the remainder of the bleach, will it just be less potent? or will it be fine?
As long as it's not mixed up already, then yes it'll keep fine. If it's mixed then its useless after an hour.