Just as an observer, it looks to me like the contestants bring kerosene, oil, and ether to the contest and mix as they go along.
Since the Richard Pryor free basing incident ether has been branded a drug-related substance and isn't so easy to get.
I had a couple diesels for a while, but I sold them. I could not afford a special diesel car and wardrobe of diesel clothes to contain the diesel smell, not to mention the impending stinky diesel divorce.