An anonymous reader writes "Criminals smuggle an estimated $30 billion in U.S. currency into Mexico each year from the United States, most of it laundered drug money. But researchers say help is on the way for border guards in the form of a portable device that identifies specific vapors given off by U.S. paper money. "We're developing a device that mimics the function of trained dogs 'sniffing' out concealed money, but without the drawbacks, such as expensive training, sophisticated operators, down time and communication limitations," says Suiqiong Li, Ph.D., a member of the research team behind the technology. When developing the device, the researchers first had to figure out which gases money emits and how fast that happens. It turned out that the gases are a set of trace chemicals, including aldehydes, furans and organic acids." What do bitcoins smell like?