Originally Posted by wrcsixeight
About the skin forming in the can,

Propane is heavier than air. I've filled the half can with propane, and open the can a year later, no skin.

I suspect the other properties in propane,it being a petroleum product, had more to do with the no-skin result.If heavier than air is all there is to it,then I would try Argon, heavier than air no boom boom.