*UPDATED MODEL* Fuel Saving Cap for Zippo Hand Warmers

A TPU cap that goes over the catalytic burner. It is only useful if you are willing to pop the hot catalytic burner off using the top half of the handwarmer to first turn it off. Putting the TPU cap (or any flexible filament) on the burner while it is on or hot can release harmful chemicals. 

Update: added small handles/tabs to the sides to make it easier to remove, should still fit and print just as well. Thank you for the likes!

Update 2: just did a quick test to see how much it actually effects evaporation
in 24 hours after mostly filling the warmer, it went from 83~g down to 82~. I then took the TPU cap off and let it sit for a few hours, it went from ~82 to 80-81. my scale isnt super great, but this clearly shows there is a significant difference, ill give it another try with it completely full.
 

MAKE SURE THE BURNER IS OFF AND COOL BEFORE USE!
    WATCH THIS VIDEO TO KNOW HOW TO DO IT SAFELY

If you turn the handwarmer off while it still has fuel inside, this cap can prevent the rapid evaporation of the fuel when not in use. Some gas will still leak out, but if you plan on starting and stopping the handwarmer multiple times over the course of a few days, this will save you a lot of fuel. It is small enough that it fits under the outer metal cover so it does not take up any space while in use. It will not keep the fuel from evaporating completely, but it will slow it down a lot.

 I have only tested with the 12 hour version, and cant guarantee it will fit under the metal cover on 6 hour as well, but the burners are the same size for sure.

Print out of any flexible filament. I used giantarm 95a clear TPU, print with the top side on the build plate. Different hardness's of filament may need to be scaled up or down slightly to have a tight fit. It does not need to be excessive since there is still some air gap between the metal parts, but tight enough it wont come loose on its own.

To release the catalytic burner from the TPU cap first remove it from the lighter, then press down on the burner though the flexible top of the cap. It should then slide off easily.