This is old news in some ways. Most folks heard about the van that drove across the US on free used burger grease.
The newer twist is that the issue has gone bonkers online. There are lots of folks sharing their diesel-conversion project tips and stories. Old Rabbit Diesels are apparently highly favored for this project. But really any diesel will run on veggie oil. What to make of it all? Well, check out these websites for starters.
And here’s the Bible of it all by one of the guys who did the van trip: “From Fryer to Fuel”, by Joshua Tickell.
Websites: