Survial Tip: Coke Can Firestarter
Here’s a hot tip for an emergency firestarter that isn’t affected by rain. The bottom of an aluminum soda can is shaped so that it will reflect sunlight to a pinpoint spot and create enough heat to ignite tinder materials. The key is that the can bottom needs to be well-polished first. In this example chocoalte is used as the polishing material to get the soda can nice and shiny, although any good polishing material should work: jewelry polish, Brasso (probably a lot quicker), and even very fine sand.
In truth, the polished soda can bottom of this fire starter is probably a bit fragile to carry around in a pack and once the can bottom is bent or crushed it won’t focus sunlight enough to start lighting things. On very rainy days I can’t imagine you would catch enough sun to get things lit either. On top of all that, I don’t normally carry canned drinks on hiking or backpacking trips - something about hiking for hours shaking them up so much that they explode when opened. On the other hand, if you ever get stuck inside a post-apocalyptic, city-themed, sci-fi movie, you’ll know what to do now.