I have these little lens wipes that I use for my glasses, and my camera lenses and stuff. And whenever I use them, I notice afterwards like my skin feels really cold. This has isopropyl alcohol on it. You also notice this in hand sanitizer and what's happening is that of course our bodies are way warmer than the alcohol in the hand sanitizer, so the heat's going to get transferred into the alcohol. The alcohol evaporates pretty quickly mainly because alcohol molecules don't hold on to each other as strongly as molecules of other liquids, like water. Those interactions between the molecules which are keeping them in a liquid state will break when there's enough energy, in this case heat transferring into the alcohol. Because the heat increases the molecules kinetic energy, they move faster, and they tear apart from each other. alcohol only needs a tiny bit of energy to go from liquid to gas phase, where each molecule is farther apart from its neighbor, and your body heat can be that extra bump it needs. So, in the end the alcohol steals your body heat to evaporate, and it takes that heat with it as it evaporates off of you leaving you feeling cold. since it evaporates so quickly you don't need to wash it off your hands.