How much coincidence should happen so that the fire reaches the two copies at the same time in different places that have never been seen before?
The metal card seems like a good way to store, which one do you recommend?
Discussion
I'm sorry. It was late and I misunderstood you. I somehow thought 1 key split on 2 pieces of paper.
As for metal cards. I use ISO-4955 (or similar) metal plates which have been hardened and are corrosion resistant. Titanium plates are also an option but more expensive.