Sanitizers work best when the hands are already reasonably clean and the product is used correctly (right amount, full coverage, and enough contact time).

Quick Scoop

Finish the phrase

The phrase “sanitizers work best when the…” is most accurately completed as:

“Sanitizers work best when the alcohol concentration is between about 60% and 90% and they are applied to visibly clean, dry hands for at least 20 seconds. ”

Key conditions for best effect

  • Alcohol concentration is typically between 60% and 95%, with public‑health guidance usually recommending 60–90%.
  • Hands are not visibly dirty or greasy; heavy soil or organic matter should be washed off with soap and water first.
  • Enough product is used to keep all hand surfaces wet for about 20 seconds, including between fingers and around nails.
  • The sanitizer is allowed to air‑dry fully; wiping it off early reduces its ability to kill germs.

Quick comparison note

  • Soap and water are generally more effective than sanitizer for removing dirt and many viruses, so sanitizer is best as a convenient backup when a sink is not available.

Information gathered from public forums or data available on the internet and portrayed here.