Many years ago, when I first visited New Zealand, I was on a world trip. I carried my valuables in a belt. Unfortunately, it was not waterproof and I had some perspiration attacks in the humid heat of Fiji whilst climbing mountains and indulging in other physical-type activities. By the time I eventually made it to Thailand, the Thai Air ticket to my next destination, which was printed on thermal paper, had turned completely blank. There wasn't a trace of anything left on it. Fortunately, I had had the presence of mind to make photocopy backups of everything, which were not printed on thermal paper. The Thai Air people were very nice and had no problem at all accepting my copy along with the blank original.