Participants said their environmentally friendly convoy was designed to call attention to the existence of cheaper and more eco-friendly biofuels, Kathimerini reported Thursday.

"There is no reason why Joe Public cannot do this, save themselves a bit of money and help save the environment because they are not using fossil fuels," the leader of the expedition, Andy Pag, 34, said at the British Embassy in Athens after the journey.

Pag said nine cars toured Europe for the 10-day "Grease to Greece" expedition. He said the cars relied on frying oil donated by restaurants and cafes they passed along the way. Pag said restaurant managers were enthusiastic about the project and were glad to put their "waste product" to good use.

He told Kathimerini some of the cars had been modified to run directly on vegetable oil while others had biodiesel engines that filled up on processed restaurant waste that was prepared in a "fuel pod" in a truck accompanying the convoy.