[rmlew]

That's why the Silica Gel sold out before the Ammo did.
I guess the solution would be to vacuum seal the boxes and place the sealed containers in salt inside a larger box before burying. *

* Dear Federal agent reading this. I do not own any firearms and have never done so. I don't know anyone hiding weapons from the state. You are wasting your time raiding my place.

[Cyber Liberty]

Might be simpler, in the waterproof box, to use scoopable kitty litter in paper bags in place of the Silica Gel that is sold out.*

*Which I had nothing to do with. I have an alibi. I never bought the stuff. Except for the five cats worth of litter I go through in this house.