Many people believe that hand air dryers are more hygienic than paper towels because fewer people touch air dryers compared with paper towel dispensers. But studies show that in terms of hygiene, paper towels are the way to go. One study recruited sixteen volunteers who had their hands sprayed with a harmless strain of E. coli bacteria. After washing and drying their hands with either paper towels or warm air dryers, the volunteers’ hands were swabbed again. Perhaps surprisingly, hand dryers only removed 23% of the bacteria while paper towels eliminated 71%. It seems that due to friction, paper towels are more effective at dislodging bacteria from the skin’s surface. Generally, antimicrobial agents found in soap have too little contact time to exert their antibacterial effects during hand washing so bacteria are best removed by physical action as by rinsing and paper drying.