In October 2014, an internet commenter known only as jmill208 finally deciphered the hole in the felt pad at the bottom of a Zippo lighter. His findings have altered our understanding of Zippo lighters. Full text transcribed here:
“Ahhh, the felt hole.
The felt hole is a region of spacetime in your lighter from which the felt-covered fluffy cotton prevents anything, including lighter fluid, from escaping.
If there are spare flints orbiting the felt hole, Zippo uses their orbit to determine its mass and location. Such observations can be used to exclude possible alternatives (such as neutron stars and maybe evaporation). In this way, lighter aficionados [sic] have identified numerous stellar flint hole candidates in binary systems and established that the core of the Zippo contains a supermassive felt hole of about 4.3 million solar masses. This is why your fluid only lasts a week. You need a bigger can of fluid and don't, please don't concern yourself with the size of the hole. It's tough to really understand.
Hope this helps.”