The ESD bags you get with electronic components? Those are Mylar. If you think about it... Mylar is metallized plastic bags. That is why they are air tight, because just plastic alone is not. In theory, any electro-static discharge would travel along the bag protecting any electronics inside if sealed properly.
I was planning on putting them in sealed mylar ESD bags with a layer of foam protecting them from touching the inside of something like an ammo can that has been properly sealed (metal tape and grounded. Should be sufficient to protect them from any solar produced EMP. EMP in Denver area means I am already dead as I am sure most of the first-strike targets are all within 100 miles of here.