The other day, digging around in my purse, I found my lighter very hot.
I couldn't figure why that would be at first- if the button was being pushed down by something the gas would just be escaping... could it had been lit inside my purse all the time? No that didn't make sense.
Upon investigation of the rest of my purse contents I found a nine volt battery on the bottom with all the quarters and pennies and stuff. Also very hot.
So I am guessing the metal on the lighter clip part was touching the positive and negative ports of the battery creating a circuit with nowhere for the energy to go except to generate heat... right up next to a fuel source.
I wonder if it would have exploded in a blazing fire ball of acid melting my purse and burning my face off all at once?