A tree hugger friend of mine told me to use regular dish soap and mix with hot water and pour it on top the mound and around the mound to get any that are not in the mound. It really works and doesn't kill your grass and its cheap. You can also use this same concoction to kill wasps and bees. It clogs em up and they die.
disclaimer: I have never used said concoction on wasps/bees/yellow jackets because I know that diesel works great and usually have some
