I don't really know. If I were you I would mix 1/8th bleach and the rest water and put it in the washer with the denims. But use a pair that you don't really like just in case it makes it too light. I think that 1/8th bleach wouldn't work enough but you could try. If its not dark enogh like if they are still really dark try 1/4th bleach. Iff they are kinda light but not light enough then just do it again with 1/8th bleach. Whatever you do make sure you mix the bleach with water becuase if yuou just put small amounts of pure bleach on the pants it will turn them white