Before bleaching, it is best to coat your strands with a very light layer of coconut or argan oil. It's not necessary to let these oils soak. Because your hair naturally contains copper and iron, the peroxide in bleach reacts with these minerals and creates a chemical reaction, which is damaging to your hair. Both coconut and argan oils contain substances that chelate (or bond) copper and iron. Essentially the oils stop these reactions, thus reducing the damage. However, they will only protect against this specific reaction. The bleach will still penetrate and break down your hair's keratin. To achieve the best results, it is suggested to go into your appointment with hair that hasn't been washed for at least three days as the dirtier and oilier, the better!