Popcorn kernels expired July 2009. Still use?

I find that the older the popcorn kernels are, the more they stick to my teeth after they have been popped.

We go through spurts of making popcorn, and we buy it in bulk without any dating. Sometimes that means more unpopped kernels, but what does pop is fine.
In the unlikely event that you get popped corn that has an off taste, feed the birds, or compost. Nothing goes to waste!

It worked! My roommate claims it is crunchier and a but nuttier. I'm going to start stashing popcorn in closets

I meant to say enough Steam...

They've probably lost moisture & may not generate enough to pop when heated.

It's all a science experiment.

They might have lost moisture which can prevent popping. Soak them in water for a half hour then try popping.

They might be stale. Try a tsp or so and taste. Then make a big batch if still good.