Okay, I was messing around with a WetFire tab. It appears that they seal them and then gas purge them; some inert gas, probably nitrogen, is pumped into the package before it's sealed. You can tell because the WetFire package is like a little "pillow", not a tighly packed "brick."

I sealed the unopened WetFire in a 2.5" x 10" pouch in my VP215 and the results were interesting. The resulting package was a very tight package with no "pillow." This indicates that either the gas in the original pouch is very compressible or, more likely, the original package is ruptured by a vacuum that strong. A third alternative explanation is that my WetFire had a hole in the package to begin with- it didn't seem quite as "pillowy" as I remember them normally being.

All I can do is open it and see if it will burn. If it came open in my sealer I can't imagine that would hurt anything since it was sealed back up in a very strong vacuum. Of course if it had a pinhole to begin with it's hard to say whether or not it was still good when I sealed it.

I'll try to remember to take a pic after work tomorrow, and in any event I'll take a pic before I open it.