How have you been storing it for the last 2 weeks? if it's been in the fridge, I'd say what the hell, use it. If it doesn't work all you'll be out is some juice. It's not like what you make will cause the zombipocalypse or anything, nothing pathogenic can exist in anything we ferment. So even if it doesn't turn out it's not like it will cause any harm.
It could be amazing yeast, even with house mutations....
I don't get why folks are always so quick to push the panic button.... Empty out a couple cups from a gallon of cider and pitch some of that yeast....you'll be out what, 2 bucks if it fails?
*shrug*
Homercidal posted yesterday that he was just at a commercial brewery in Traverse City where they FERMENT their beer with plastic wrap on top of the fermentation vessels.