Depends a lot on what you put in the pot on the back of the stove. My grandmother did that on the farm 60 years ago, but it got cleaned out and restarted nearly every day, especially if there was meat in it. Even so, my sister and I got sick from eating it (we were 8 and 10 years old then), since we had not built any immunity to whatever bugs she was cultivating there. Just not necessary to do that, even in a grid down situation.