Put cinnamon down anywhere they are coming in. Sprinkle liberally. They will not cross it. If you can find their trails outside going towards your home (or anthills), cross those with some too. I buy bulk at the co-op and use my own container, so it's not expensive. (know the weight of your container so you can tell the cashier and they should reduce the product weight they charge you for accordingly) I keep a margarine sized container full on hand, since I live in the wild and there are more of them than me.