I mean you can just take white phosphorous to a warm place and let it spontaneously combust. The use case would be materials that don't burn at the Earth's sur

I mean you can just take white phosphorous to a warm place and let it spontaneously combust. The use case would be materials that don't burn at the Earth's surface temperature, but do burn at the Moon's peak surface temperature. But you could probably get those hot enough just by rubbing them or something.