Your hands, up close, are anything but smooth. With peaks and valleys, folds and rifts, there are plenty of hiding places for a virus to stick. If you then touch your face, the virus can infect you. But there are two extraordinarily simple ways you can keep that from happening: soap and water, and hand sanitizer. So which is better? Alex Rosenthal and Pall Thordarson investigate. Lesson by Alex Rosenthal and Pall Thordarson, directed by Artrake Studio.