Does your hair need to be clean to dye it?

Not necessarily, it depends on the hair color process you would be using.

For lightener your hair does not have to be clean as you apply it to dry hair.

For a semi-permanent hair color it can be applied to dry hair and or towel dried hair.

Temporary colors can also be applied to dry hair or towel dried hair.

Read the directions on the back of the color application and the directions should tell you whether to shampoo and towel dry or apply to dry hair only.