They grew corn they found in Mesa Verde that they figured was about 1200 years old and they popped seeds they found in a Mastodons stomach that was frozen in ice for a few million years. If you dont have that then I store them in a prescription bottle in the freezer or fridge and I have popped them after 7 years.

Like ChAs420 said, you can nick them or sand them a to thin out the shell a little to give them some help. If your a butter fingers like me  you line the inside of a matchbox with sand paper drop the seed in there and shake it around. Soaking them in water for 24 hours can help too.