We have hundreds and hundreds of wasps throughout the spring and summer. Our grand-children get stung repeatedly if we don't keep the numbers under control. The easiest and cheapest solution for us, so far, has been that gold-colored "Lantern Oil". This lantern-oil is not the same as Coleman fuel. We apply it using a 1-gallon pump-up bug sprayer. We don't usually fill the sprayer up. A quart or two is usually enough for us to kill all of the wasps in one pass around the property. If we can get right up to them, we use a very short blast on a narrow spray pattern. If we must shoot from far away, we use a straight stream and, that will reach 15 feet high! The oil kills the larvae inside the nests. And, any wasps that were off the nests when we sprayed, abandon the oil-soaked nests. As soon as the spray hits the wasps, they drop like they've been pole-axed! They don't flap a rotten little wing. If a little oily residue bothers you, a quick blast with the hose rinses it off. However, I leave the residue in most places because they don't rebuild a nest where the residue lingers. No beneficial "bees" are harmed using this method.