Hands are one of the most important body parts containing microorganisms and spreading diseases. There are two types of microbial flora on the hands.
Resident skin flora—consisting of microorganisms that colonize the skin and become permanent residents. They can never really be removed completely, even with a surgical scrub—but can be reduced.
They can actually exist several layers beneath the surface in the stratum corneum. Although they are capable of causing infection when spread to others, transient skin flora are the real culprits. Transient skin flora are a major source of contamination and disease spread, but do not stay on the hands for long periods (they come and go). Fortunately, the microorganisms here can be removed during handwashing and/or hand sanitizing.
So, how should one clean their hands?
The mechanical action of handwashing with antimicrobial soap and water is important to remove dirt, debris or any visible soil. When hands are not visibly soiled, hand sanitizing has been proven to be effective in hand antisepsis, but only when performed correctly, by rubbing hands until the gel/foam dries).
Happy Hand Antisepsis!
Sources:
Miller, C. & Palenik, C (2005). Infection Control & Management of Hazardous Materials for the Dental Team. St. Louis. Elsevier Mosby.