I'm so glad I found this! I dyed my hair black, like I always do. I'm naturally a brown/black and I dye to cover the grey. Well, this time it came out awful. It looked like I dipped my head in a bucket of black shoe polish! First I tried washing it in Dawn dish soap and that helped a little bit. The next day I went to the drug store and got some Vitamin C gel caps. I split them open (six of them at 500mg each) and mixed them with about a table spoon of baby shampoo. Now, this is the step no one has mentioned so far, I wet my hair down before mixing in the shampoo and vitamin c. Don't know if I was supposed to do it that way or not. It might have worked better without wetting it first. If I ever have to do this again, I'll definitely do it on dry hair! Either way, I left it on for about 45 minutes because I didn't want to lighten it too much, just take the terrible flatness out of the color and lighten just a little bit.
Anyway, it worked out just great. My hair is still black but it's a natural black now and I even have some highlights to it. This worked perfect for me and I'm sure that if I'd used the powder and left it on longer, I could have lightened it much much more! Thank you!!!