"I carry hand sanitizer as an easy way to clean hands after bathroom use, etc. No water, soap or towel is needed."
From a March 21, 2006 article in the New York Times -
"Since 2002, officials at the Centers for Disease Control and Prevention have recommended that health care workers routinely use high quality alcohol-based gels instead of soap and water on their hands when moving from patient to patient — as long the worker's hands aren't visibly soiled.
“Alcohol doesn't cut through grime well, so dirt, blood, f.e.c.e.s or other body fluids or soil must be wiped or washed away first, if the alcohol in the sanitizer is to be effective. In such cases, hand washing with soap and water is advised.
“How much goop should you use? Vigorously rub all sides of your hands with enough gel or foam to get them wet, and rub them together until they are dry. If your hands are dry within 10 or 15 seconds, according to the C.D.C. guidelines for health care workers, you haven't used enough.”
Also noted was the fact that there are sanitizers out there that are less the 60% alcohol -
"I used to work in a virology lab," Dr. Aiello said, "and we knew — it has been known for decades — that an alcohol concentration under 60 percent won't kill the microbes. It's really frightening to think that there are products out there that contain levels lower than that."
So, just in case a critical point was missed -
Scrub with soap and water. Rinse. Then use a good sanitizer.