For several years I've been using the orange plastic screw top match boxes from Coghlan's for similar jobs. Useful for storage of things like: pills (medications, water purification, etc.); condiments/food (instant coffee, sugar etc.); I put tinder in another, and even matches in one. Just mark the contents with a black sharpie.

I keep one in my pocket with my daily "pills." I found they work really well for this because they seal tight and keep out the humidity which destroys most medications. I found that commercial "pill boxes" didn't and came open in my pocket.

Haven't given it much thought, but I don't think it would be hard to rig up a ring or something to use it with a lanyard.

If your careful, you can even get a spark off the "flint" in the bottom.

And at a dollar or so (last time I bought a bunch) you get a couple for the cost of one Keep2go...