Jed Klampet shot varmints to find his billion-dollar oil well. Teh Fu Yen, Ph.D., a professor of environmental and civil engineering at the University of Southern California School of Engineering, developed an inexpensive filter instead. "In preliminary tests, our filter removes as much as 60% of the sulfur [from crude oil] in a single pass," says Yen. To make the filter, an engineer heats a mixture of two metals to nearly 1,000F and sprays it through a nozzle. Emerging as a fine crystalline powder, this "intermetallic" substance is bonded to an inert substrate, such as carbon fiber. The coated substrate is then packed into a hollow glass cylinder--creating a large interior surface. The greater the surface, the higher the efficiency of the filter. To remove sulfur, Yen treats the intermetallic powder with particular chemicals to produce a crystalline structure containing small pits that match the size and shape of sulfur molecules. "The crystalline structure can sort out the bad without affecting the good," says Yen. "Analogous methods of nanotechology might also be used to remove nitrogen compounds, metals, and other impurities. South America, China, Canada, and certain republics of the former Soviet Union have large reserves of crude that are heavily contaminated with sulfur, metals, and other impurities. Intermetallic filters could purify such oils both efficiently and economically." By altering the crystalline structure, variants of the intermetallic filter might also be used to treat sewage and purify wastewater, Yen suggests. E-mail to email@example.com.