How long do you leave toner on your hair?
Mix your toner with a developer in a 1:2 ratio. Use an applicator brush to work the mixture into your hair, focusing on the areas with unwanted undertones. Leave the toner in for up to 45 minutes, then rinse, wash with a moisturizing shampoo and deep condition.
Do you have to apply toner to wet hair? Not at all; you can apply toner to dry hair. You will get much better results if you apply it to damp (not wet) hair.