Safest way to carry a spare battery or two would be a
plastic battery case:
Plastic Battery Cases
Contact with metal objects, whether it be keys, coins, or metal zippers can complete the electric circuit of a battery causing it to over-discharge and go into thermal runaway -- battery melt-down. Below is an AW IMR battery which was being carried as a spare in a book bag pocket and obviously came into contact with metal. The inner components of the battery casing have vented out the top of the battery. Imagine that happening inside your pocket or mechanical
mod!
Your Nemesis should have a
safety lock for the bottom firing switch. Always engage this safety feature when not
vaping and especially if you carry the mod in your pocket. Removing the
juice attachment while transporting the mod is another alternative (this essentually removes the ability of the battery completing the electrical circuit).