Hand sanitizers work by stripping away the outer layer of oil on the skin This usually prevents bacteria present in the body from coming to the surface of the hand . Experts say washing with soap and water is first choice, especially if you have visible dirt on your hands. Sanitizer can't cut through that grime . Hand sanitizer is great for when you can't get to soap and water, and it's actually more effective at eliminating germs because it kills them rather than just removing them .