If you wanted to store them correctly...you should store them in an airtight container.
I have heard everything from plastic baggies, plastic film containers. to canning jars. What ever works for you. I have always stored them in envelopes but I have sowed them usually that winter.
In the freezer I have heard they store for years.
I have kind of given up on seeds for the most part. It's culling the seedlings that I have the hardest to do. Suppose I could start passing them out to the neighbors....