way to transfer cold germs is physically by touch. A survey of subway trains in Boston found that metal poles are a fairly hostile environment for microbes. Where microbes thrive is in the fabrics on seats and on plastic handgrips. The most efficient method of transfer for germs, it seems, is a combination of folding money and nasal mucus. A study in Switzerland in 2008 found that flu virus can survive on paper money for two and a half weeks if it is accompanied by a microdot of snot. Without snot, most cold viruses could survive on folding money for no more
