A standard field expedient water heater cooker is a oil/water heated plate unit. In essence teh water exploding into steam causes the oil to be atomized and so you can burn oils that wouldn't normally work. A common used combination is diesel fuel, or kerosene mixed with as much used motor oil, bunker fuel, or waste oil as will burn smoothly.

The advantage of a fuel/water burner is that it works well for heating water and cooking, can be assembled in the field from scrap metal, and it greatly extends your fuel supply by effectively burning thick waste oil, grease and anything else as long as it is mixed with a bit of the good stuff so it can drip and be metered.

The key to lighting it is to preheat the burner plate with a small pile of wood soaked with kerosene or diesel. It really needn't be red hot, perhaps just a dull red if seen in the dark. It is hot enough if a drop of spit explodes on contact. If it sticks to the plate and then boils off it isn't hot enough yet.

I have previously seen DOD publications that give instructions for assembling and running one but don't have the location handy. You can probably find it by Googling some mix/combination of "water heating", "oil-water burner", "flash burner" "Special Forces", "sanitation", "field expedient" should work.

I would do it for you but the exercise will do you good.