Similar to what Garth describes using car exhaust to kill bees would be to get a tank of CO2 and after closing all entrances and cracks, give them the CO2 from the tank. In the beginning it will knock them out (like an anesthesia ) and then if you continue doing it, they will suffocate. I would imagine bees would probably die pretty fast if they can't breathe. Almost all insects have an automatic response to Carbon Dioxide, which is to breathe more. They can't stop breathing. That is why we always used CO2 to knock out and anesthetize insects before using them in experiements in our insect physiology class. People who collect hornets nests use it to knock out the hornets temporarily while cutting down the nest and putting it in a plastic bag for transport. People who want to safely store grain in an airtight container often will put dry ice in the bottom. As it sublimates and releases CO2, this dispaces the oxygen because the CO2 is heavier than oxygen. Any insects in the grain will be asphyxiated and die. Then you push the lid down tight and will not have any insect problems in the grain. I imagine you could put a piece of dry ice in the bottom of the hive and seal up everything airtight (as much as possible) and also have the same outcome as Garth describes (it ought to take an hour or more for the dry ice to all sublimate). I would think that the dry ice would cause no lingering problems of toxicity or smell, etc. such as might be caused by using petrol (gasoline for Americans) or burning sulfur fumes or one of many other alternatives. I suppose one could even use chloroform if one had any. Dry ice seems to me to be the cheap and easy way to go with no toxic after affects. I probably wouldn't have thought of it except for Garth's post on using car exhaust. Layne Westover College Station, Texas