Well any pipe tobacco boxes (tins) are waterproof. Problem is they will have silicone seals on them and when you use them to boil water there goes you tight seal next time you close it. I think that would go for any waterproof box out there as well. Unless you make your own o-ring and remove it before boiling.

I switched from metal tins to otter plastic boxes which are great for everything I do.

Matt