After you drill the hole (I use a 1/2" butterfly bit), just run a bendable piece of wire thru it, and out the pour spout. Then run it thru the cap end of the valve stem and put just enough of a kink in the wire at the bottom of the stem to hold it. Pull it back thru the can until it pokes thru the hole you drilled....and pop it in place. Pull your wire out....and you got a vent! :D
