Testing CO Detectors

[newalarm]

I have some CO detectors in the house. I picked up a can of CO check by HSI Fire. That can seems empty. I tested on CO when I got the detector a while back. Went to use it again and nothing happens. The instructions says you need to spray can into an application tool, but does not explain what this tool is.
 
I called HSI Fire. They say you get one or two uses out of each can. You have to spray it at the detector until it goes off.
 
How have people here tested CO detectors?
 
Thanks.

 

[Del91574]

You use the test enclosure to keep the tester from mixing with outside air...no different than what you're supposed to do with smoke detectors (we don't use punks any more or spray randomly into the air by the detectors).
 
I can't comment about the weight or if the can seems or feels empty to you.