That's exactly what a scientist is doing: she digs for platinum. In fact, she's not even digging, she's just searching for the precious metal in the dust on the roads and she estimates many kilograms of platinum are being sprayed onto streets and roads each year.

Platinum comes from an unexpected source: cars. This precious metal has recently become even more valuable (it is more pricey than gold) due to new industrial applications that interrupted the jewelers' exclusivity in using this metal.

Most car manufacturers use platinum as a catalyst in the catalytic converter, an optional (though often mandatory by law) component of the gasoline-fueled automobile exhaust system, or as a catalyst in hydrogen fuel cells and even in sophisticated sensors.

However, over the years, even the most technologically advanced catalysts are slowly losing platinum, which is then sprayed on the roads through exhaust pipes. This is why Dr Hazel Prichard, from the School of Earth Ocean and Planetary Science, at Cardiff University, UK, estimates such large quantities of the metal to exist in dust covering the roads.

Along with her team, she wants to recover platinum waste in a project hoping to develop new recycling applications that are cost-effective and sustainable. Mechanized road sweepers are also a good source of platinum and she is now trying to find the approximate locations where the metal is concentrated enough to recover.

Dr Prichard said: "Platinum is a vital component not only of catalytic converters but also of fuel cells. Fuel cells are an important new source of clean energy. Platinum is a precious metal and resources are scarce and expensive. Our research is looking at ways of recycling platinum and other precious metals."

The final goal of the entire platinum-digging project is to find out how to create new techniques of producing environmentally friendly fuel cells, which will be able to produce clean energy while minimizing waste.