YOUR HAIR NEEDS TO BE DIRTY WHEN YOU ARE GETTING IT COLOURED.
The truth is that your hair will take colour better when it is clean. The only thing that can cut through dirt, grime and hair product would be lightener (aka. bleach). This is what I tell my clients... If the words come out of your mouth "I am so sorry, my hair is so disgusting right now." Then you need to wash your hair! Courtesy wash for you and your hairstylist. Put yourself in your hairstylists shoes and think if you were them and how you would feel to look, touch and smell hair that is dirty, oily and gross. Even if you are not getting your hair coloured, it is best to have your hair washed and clean or a day old is ok. This is so the hairstylist can see how you like to wear your hair and also to see the condition of your hair and scalp. I swear your hairstylist will appreciate it more than you know and you will feel better about it too.