How to make karengo They use hot water to wash the karengo but there’s one thing that you have to do. You wash it carefully and when you finish washing it you put it in a bowl then you put it in the oven. When it ready you take it out of the oven and put butter in it. While you do that make sure it is not to dry, if it is you put a little hot water in the bowl. Enjoy and eat.