1.   Manufacturers are working with new fuels to find one that burns more cleanly than petrol.

2.   This fuel burns more cleanly than other fuels.

3.   Because the fuel burns so cleanly, it may have applications in cars as well as light trucks, said Sara Tatchio, a Ford spokesman.

4.   Administration officials say their decision was a matter of air quality and current law, not politics, explaining that ethanol allows gasoline to burn more cleanly.

5.   The gas burns more cleanly than the fuels themselves.

6.   The gasoline helps cut smog by burning more cleanly than conventionally blended gasoline.