Just like your laundry needs a rinse cycle before you add detergent, hair should be thoroughly wet before you add your shampoo. “Hot water will open the cuticle, which is good for removing any dirt or product trapped in the hair,” says White. Another bonus: “When your hair is rinsed in warm water, it loosens the oils through the scalp and opens the cuticle so it is able to absorb the oil” in your conditioner, says Saviano.