I had a client come in today for a consultation. about 6 weeks ago she put a dark brown box colour on her hair and hated it because her grey roots came through too quickly. she the went to her salon and they bleach bathed it. she now has come to me and asked if I can put a full head of highlights in. I have taken a test cutting to see if it will take bleach with 20vol as I don't think anything else will lift it. any advice. Thanks in advance.