Said SPI: "It was right at our, um, fingertips."
An SPI spokesman angled his iPad2 under a lamp, pointing out the smudges on the screen. "Oil," he said, "Grease. The stuff of fingerprints."
The icky substance is a naturally-secreted hydrocarbon that can power a lawnmower, fuel a space shuttle or light a major metropolis. "Think of the billions of touch-screen devices that Apple alone has sold," he said. "iPads, iPods, iPhones -- this is a mother lode of combustible slime."
And how to harvest the gunk? "Ship old devices to a Third World sweat shop and let them scrape it off."