Knowledge: To make hair grow longer, "Horse Hair" shampoo is wonderful to use at home, lets it shine and will make hair grow longer. On the other hand, any hair soap that is color purple will allow your hair dye stay pretty as the purple will prevent any color change.

Conversation:
I love to color my hair. I recently colored it purple.
How interesting! Did you do it yourself or did you go to a professional?
I did it myself at home. Is there a shampoo to make it last longer?

Response: Oh yeah, any hair soap that is color purple will allow your hair dye stay pretty as the purple will prevent any color change.