All right, I'll admit it: the first thing that popped into my mind when I saw "grease car" was "It's Automatic! Hydromatic!" from the movie "Grease." I thought it might be a name for a late 50s car. But I see it's one of those cars that runs on French fry oil.
This is not a bad idea. It's a great way to reuse, repurpose and recycle. With gas going up every day, it makes me wish I had the money to convert my car to run on cooking oil!