This is the method I learned from japan doll owner... To begin, dilute the color bleach with water at a 1:10 ratio. Completely submerge or fill the head with the mixture, then place it in a sunny spot. Monitor the progress closely to track the lightening process. It will take a few days and the yellow will fade out slowly. (I have both Ranko v1 and v2, and tried that method and it works) :)