Here is another vintage idea from the old Ogden cigarette card collection. This card shows how to use a bucket with a hole drilled in the bottom for an emergency water filter.
According to the back of the card, this cigarette tip was Boy Scout Tip 47 issued by W.A. and A.C. Churchman, a branch of the Imperial Tobacco Co. The back reads:
“A most handy and efficacious filter can be made out of an ordinary perfectly clean zinc water pail, through the bottom of which a hole has been drilled and a small pipe fitted. The water percolates through the layers of fine and coarse sand, and clean picked gravel and stones, with which the pail is filled, filtering through to the bottom in a clear state.”
Just a disclaimer note that this vintage useful idea is from a century old cigarette tip card and health precautions should be observed before using this technique.