Here are some facts about hand washing from the Oregon Department of Health Services:
Hand washing is the single most important thing you can do to avoid the flu or to avoid spreading illness. Adequate hand washing requires soap & clean, running water. Warm water is preferable. Lather up & scrub for 20 seconds.
Why use soap? It mixes with skin oil and loosens grease and dirt that may hold germs. If not available, use an alcohol-based gel as a substitute. Plain soap is a better choice than antibacterial soaps.
Wash your hands often. The average person touches eyes, nose, and mouth at least 200 times a day.
The most important times to wash hands are before preparing or eating food, after going to the bathroom or diapering a baby, before and after caring for someone who is sick or bleeding, after blowing your nose, coughing or sneezing, and after handling an animal, animal waste, or garbage.