Lines of drivers cleaned-up and fueled-up their engines for free to celebrate the all-new Shell Nitrogen Enriched Gasolines which contain a unique, patented cleaning system designed to seek and destroy engine ÒgunkÓ in all three grades of gasoline. Shell Nitrogen Enriched Gasoline Spring Clean-up Giveaways took place in seven major markets across the country, including one event at this Shell gasoline station in Ardsley, N.Y. Friday March 6, 2009. (David Goldman/AP Images/Shell)