While washing our hands with soap and water is the best way to reduce germs, the CDC says that hand sanitizers do indeed work if there are no sinks to be found around you. The CDC also cautions that not using enough sanitizer, or wiping it off before it has dried completely, can cut down on its effectiveness. With this in mind, follow your sanitizer directions properly, and let it dry before doing anything else with your hands. While hand sanitizers can do their job properly on clean hands, if your hands are really greasy or dirty (from activities like sports, gardening, camping, etc.), they may not work as well.