Good for ammo, extra sets of keys, money, that automatic trigger group you’ve been working on for your AR.
Just don’t forget where you bury them. A good way to remember is to make…I forget the technical name, but I always call them resource maps. Basically its either transparency sheets or a thin material you can lay over top of a map and still see the map. Without the map it looks like a trash piece that got screwed up in the printer. Over the map if situated right you’ve got exact locations of your caches. I’d do multiple layers, each layer being for something different.
You can do it on a full size version of your property appraisal map, but scaling it down makes it easier to hide.