Colour B4 Extra Colour Remover. Colour B4 shrinks the artificial dye molecules in the hair, enabling you to simply wash them away. What?s more Colour B4 does not touch your natural hair pigment so you are left with the colour which lay beneath your artificial shade. Colour B4 takes you back to your lightest shade. It will return your hair to its natural colour if the artificial hair colour applied is darker than your natural level.Hair colour remover is perfect to wash away your unwanted artificial colour.