Hmph. Interesting thread to find upon my return to D-Web. I have just about finished spending the last few weeks using up some slightly stale gas from my jerries -- which all had had stabiliser added, but most of which were a couple years old fuel, and a sniff test revealed that they had started to go off. Like one of the other replies said, mix it with fresh, but I would strongly suggest using it on your biggest gas guzzler -- i.e. your truck -- and trying to use it all QUICKLY. Stale gas mixed in with fresh works, but it will catalyse the fresh gas to turn stale that much quicker. Also presence of all that fresh air (and oxygen) in top of the fuel tank does not help any. Ergo, I have been mixing 10 gallons of old with 10 gallons of new in my fuel tank right before making longish road trips. Another couple of trips and I should be all done.
The other reason I am doing this is to switch from some older cans to some newer ones. The older ones will go into basement storage, so in preparation for that I have been draining them (leaving the spout open and at the lowest point, so as to allow the vapors to come out) and will purge them with CO2 before storing them. This should serve to make them pretty safe. Bear in mind that a sealed container of gasoline vapor mixed with air is arguably much more dangerous than a sealed container of gasoline.