How Parry Soap Works
When you wash your hands with soap, soap molecules bind with both the water and oil. Then when you rinse the soap carries away the germs with the water.
The most effective hand washing method is to work up a lather because the friction helps lift dirt and oils from your skin. How long you should scrub depends on how dirty your hands are, but most health authorities recommend at least 20 seconds, or as long as it takes to sing "Happy Birthday" twice. And don't forget to scrape underneath your fingernails or on the top side of your hands.
Once you've washed, air-dry or towel-dry your hands. Wet hands are more likely to spread germs than dry ones.