California put the kibash on home made diesel here. Was a big thing. People had contracts to pick up old used cooking grease. Behind a Benz diesel smelled like MC Donald Fry's
The only people I knew who did it had a dual tanks, and at the time access to free waste cooking grease. Yup. I could smell him coming. I always wondered if the dog knew it was him by the sound of the truck or also its smell. LOL