Wavedancer.......Your post about how chemical warmers work makes me wonder: When people complain that their warmers don't last as long as advertised, could it be because the warmers are simply too trapped inside a boot or glove, not getting any air, and so "fizzle" out sooner than expected? Meaning that if your chem warmer cools off an hour or two into your ride, you could maybe expose it to the air briefly (taking off boot or glove for, say, 15-20-even 30 seconds, if you're game ) and nudge it back into action again?