Chlorine dioxide and iodine based tablets both are highly corrosive and rely on their interaction with oxygen to work. In a few days, with luck, they'll be at a fraction of their effectiveness if not completely dead. And your pill fob will be the worse for wear.
If you want to play the repack game, iodine tablets are your best bet. You need a small glass (!) vial with a teflon cap or a cap with a teflon septa (little disk that goes in the top of the cap). Don't try to fake it with teflon tape, doesn't work- voice of experience. Although a winding of teflon tape around the threads for security is a good idea. Keep that lid down tight, and keep it in the dark if you have a colorless vial. Keep in mind that once you open the factory vial, the clock is ticking, you've got 6 months, maybe a little more but why gamble it.
A 5/8 dram bottle works well, and you should be able to fit one in a medium sized pill fob. Doug claims he can get 25 or so tablet in one, I can get 18.
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-IronRaven
When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.