I remember as a kid going out with my uncle during the winter down on the Gulf Coast to catch rattlesnakes. We would find a giant gopher tortoise (not many of these left since they cut down all the long leaf pine) hole where the snakes would den during the cold. We would run a garden hose down and put some gasoline in the hose and blow. The fumes would run the snakes out and we would catch them as they would be sluggish in the cold.