How does hand sanitizer spread germs?

Hand sanitizer can spread germs if it is not used properly or if it contains insufficient alcohol content (less than 60-70% alcohol). If hands are visibly dirty or greasy, hand sanitizer may not effectively kill germs, leading to their spread. Additionally, if users touch surfaces before the sanitizer has dried completely, they can transfer germs back onto their hands. Lastly, using the same container or pump without cleaning can also lead to contamination.