Hand sanitizer is required to clean and disinfect hands when soap and water are not readily available. It typically contains alcohol, which helps kill germs and bacteria on the skin's surface. Available as a non-sticky solution, it is convenient to use and often used in healthcare settings, public transportation, and other high-traffic areas to help prevent the spread of illnesses. However, hand sanitizer should not be used as a substitute for regular hand washing, especially when hands are visibly dirty or contaminated with bodily fluids.