co2 chamber

[justin4snakes]

i just started breeding rats and the adults are very hard to kill with a pencil and pulled tail method. juss wondering how can i make a homemade co2 chamber. i was told by someone at my local pet shop that you can take the co2 canisters from a paintball gun, put the rats in a sealed container and fill with co2. what are your ideas? thanks in advance.!