Hi...If it were me, I would go to a professional salon, and explain your problem to see if they could help. It would probably be much easier and you would get a much better result, with less damage to your hair. I had to have dye "stripped' from my hair several months ago, from where I had been dying it for at least 6 yrs. I am very pleased with the result. That's the best solution I know.
Hope it helps