I currently have blonde highlights in my hair done at the hairdressers (last done in November so I have a couple of inches of roots). My hair is naturally mid-dirty blonde but with increasing greys at the roots. Unfortunately I can no longer afford salon highlights so want to start dyeing it myself at home to cover the greys. My concern is can I use home dye over salon highlights? If so what's the best approach? Please no-one tell me to go to a hairdressers - if I could afford that I would but unfortunately I can't. Thanks