I never knew this but you can easily can butter. I normally buy butter on sale and freeze it but we like to "prep" here on the farm so we try to think of ways to preserve food without electricity. I really feel like butter would be an amazingly rare and valuable commodity should the world end as we know it. Here is a link to a great video about how to can butter. I think it is fun to think of things that may not be that valuable now but should an end of the world situation ensue they would become very valuable. For example, our debit cards would be useless and we would suddenly find ourselves trading bullets and canned goods for survival. Something to think about. Happy Canning and Happy Prepping!