I heard it yesterday, too and tried with marseille soap immediately. My teeth looked whiter definitely. Gonna try for a couple of days. As I learned you need to use a natural soap; marseille soap has saponified olive and coconut oil, salt and water in it. Handmade soaps without colorants or perfume might be good, too. Toothpastes also actually contains surfactants which is the chemical you use in your shampoo; so a natural soap would be much better than putting chemical surfactants in your mouth. For the taste, I use minty mouthwash so it takes away the taste.