I was a garbage pale kid when I was younger. Sometimes I would go to the bathroom and NOT wash my hands. Here's how I cooked the scene:
  1. Flush and zip up SLOWLY
    Time is your friend. If you wanna fool the fuzz you're gonna have to keep calm and run out the clock.
  2. Turn on sink, let run AT LEAST 30 SECONDS
    Relax, Boy. Just stick to the plan. Deep breaths...
  3. Wet tips of fingers, drip a couple drops on soap dispenser
    NOTE: If bathroom has bar soap, swipe wet fingers over bar several times to produce lather
  4. Drip a couple drops of water near sink lip and over general path your hands would have travelled to soap
    Not too much! You don't want the authorities to get suspicious...
  5. Wet fingers final time to dampen hand towel ever so slightly
    NOTE: If using disposable paper towels, crumple LOUDLY between dry hands in case any rubber necks are listening.
  6. Wait an extra ten seconds just for good measure
    You're almost home-free, you beautiful son-of-a-bitch!
  7. Exit bathroom either rubbing hands together or waving to 'air dry'
    A theatrical bonus to put anyone's minds to rest.
  8. You did it!
    Now you can continue living as the reason plagues start!