captain legend
napalm can also be made with styrofoam and gasoline. but fire is inefficient against zombies when they are near your haven/compound. napalm doesnt burn out for awhile, and the zombies, not knowing they are on fire, will likely set objects around them on fire as well.
Although if you've gotten to the point where zombies are the ones being hunted fire can be useful, as the zombies may also set nearby companions on fire.