Minor Zippos can heat things while closed or empty

[Superlagg]

I managed to use an empty lighter to burn my way through a hallway full of kudzu, heating and refilling a beaker of welding fuel over and over until I jumped out a window. Wouldn't have been able to do that with a welder!

[medsal15]

This is how I heated paper to over 1k Kelvins once. Without burning it.