On a couple occasions I've found that the flint from old cigarette lighters (> 5 years) has simply disappeared! Both times they were indoors, no climate extremes. Plus the seal on one jammed open and butane spewed everywhere...
Steve
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"After I had solaced my mind with the comfortable part of my condition, I
began to look round me, to see what kind of place I was in, and what was
next to be done"