Has anyone got any good tips on how to (cheaply) waterproof a geocache or letterbox? Those pill pots used to work brilliantly - one inside the other - but now they seem to be rather hard to come by and while the typical sandwich bag inside a container seems fine for a while, after a few months things seem to start getting wet.

Are there any more sure fire ways of keeping the contents dry?


Use an ammunition box - commonly found at Army/Navy surplus stores or on eBay/Craiglist for ~$10 USD, depending on the caliber size of the box. .50 caliber boxes are larger than, say, 30 caliber.

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Waterproof, cheap, and very durable.

Another option is to use Tupperware or something similar if a smaller size is desired. Buy higher-end containers that will be much more durable:

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  • +1 because this is great for the larger caches, but sometimes the size just isn't viable in certain locations and you need something smaller :-( – berry120 Jan 26 '12 at 0:20
  • see updated answer @berry120. – studiohack Jan 26 '12 at 0:33
  • Thanks, I have been using cheap tupperware like containers but perhaps I just need to bite the bullet and spend a bit more on something a lot more durable! – berry120 Jan 26 '12 at 0:34

A gallon size water jug like this works well, too, although I did have a bear tear apart one in a geocache because it apparently associated that kind of plastic with food.

  • how is that practical? I may be asking a obvious/dumb question here, but how do you get things in and out of it? – studiohack Jan 26 '12 at 1:24
  • You just screw off the wide lid to access the stuff inside. It's waterproof, and just about the right size. I should have clarified... I meant something like this: amazon.com/Coleman-3000000JUG-1-Gallon-Jug/dp/B00363RSXU – xpda Jan 26 '12 at 2:45
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    oh, like that. I was thinking more of a gallon/two gallon jug that apple cider or bottled water comes in at the store... +1 to you, I like that idea. – studiohack Jan 26 '12 at 3:40

I prefer the rubbermaid containers of various sizes that lock with tabs on all four sizes. You can get small ones right up to very large containers for any size of cache you need.


The 'Lock & Lock' brand works well as the four-side locks ensures the seal is tight.


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