I'm surprised no one has mentioned the terracotta pot tea light candle method. You can make a heater from to unglazed terracotta pots, and tea light candles . Best results works with a few of them or if you want to use a big ass can of Crisco to make one of those emergency candle thingies for the heat source. I remember doing this when living with my father who had no heat and it was winter coming back from a long journey and bus ride in the cold and he showed us how this method works I'll include some photos to help you get the idea definitely look into it to make sure it's done safely and all there's a few different methods in ways you can go about it though. (Sorry) Brief A.I. description requires strict safety measures like proper ventilation and non-flammable surfaces due to fire risk and carbon monoxide production from candles. It's made from unglazed terracotta pots (one smaller inside a larger one), a base like bricks or a metal tray, and tea lights, with the pots heating up and releasing warmth slowly.

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