Poison for gophers. For moles, bait a rat trap with bacon grease, place near hole in run, cover with bushel basket to keep it dark and tasty smelling. Repeat. Compliments of Wisconsin Public Radio. CO2 maybe should have been CO which is quite effective. New thread idea convert your gasser to a lethal gasser. Also, propane or acetylene are heavier than air and will displace enough oxygen to kill in a confined space, CO2 might do the same.