How to use dry shampoo: Shake vigorously. Hold can 8-10 inches away and spray onto roots. Massage thoroughly with fingertips and brush through. No water required - no need to rinse. Style as usual. What is dry shampoo? Dry shampoo is spray-able, waterless shampoo in powdered form, designed to freshen hair without soap or water. It revives limp hair, and absorbs excess oil leaving hair fresh and care-free.