 After you've put the saltpeter on there, it works a lot better if you do that first and then put the briquettes on top of that and make sure it's dangerous, you know, to leave it by itself. Keep an eye on it while it's still burning, and it'll just smolder that stump right down to the ground and be gone. If you just do the potassium nitrate, saltpeter, and you don't do the briquettes, it will kill the stump very effectively.