How does one go about purging a new can of propane?<br /><br />I was curious, as I bought a couple new 50# cans, and I'm sure all the air hasn't been purged. They've only been filled once so far.<br /><br />I can crack the side valve on one of them and get what I assume is air. No white-ish liquid like the propane does when the station fills it.<br /><br />Can I let this air out until it spits propane?<br /><br />Should it spit this propane when there is ANY amount of gas in it.. For example, if the tank only half filled, should it still spit propane out of the valve?<br /><br /><br />Thanks,<br /><br />H.