I had to use dish soap to clarify when I had a buildup problem from product overload back in March 2014. I clarified about 6 times with dish soap before my hair returned to normal. I didn't use Dawn though, just my usual dish soap (Sunlight dishwashing liquid). The advice was given to me by a local hairdresser.
This was the hair problem I was trying to deal with - not a pretty sight.
It worked well.
Bookmarks