Another material is the 'foil tape', self adhesive, aluminum, usually 1 1/2 to 2 inches wide.  Stays in place on it's own.  I've seen it at car parts (autozone, etc), as well as Walmart/Target.   
Down here our passport cards are issued with a foil lined 'protector' so I do believe this is 'real'.  I now use an aluminum wallet, plan on a leather one with the foil tape later.