My mother's friend dyes her hair with tea. Now, she is a redhead. I asked her about details, so here it is. First, it must be strong, black tea. You should rinse your hair in it for couple of minutes and repeat it from time to time after washing your hair with shampoo. It may take even a couple of weeks until you see the results. I must emphasize that I haven't tried it myself. If your natural hair color is very dark, it might not work.