Ok, I have a costomer that wants,a tree down for 2 reasons , the main reason is the roots keep getting into his neighbors pipes and causing damage. They've twice paid to have them cleared out. He really wants to help his neighbors out. He also wants it down because it's hanging over their house, my question is. What's a good treatment to put on the freshly cut stump to kill the roots? I don't do spraying or anything, but it seems like something I can do easy enough.