What about hand warmers? If you had one hanging inside a bottle would it use up all the oxygen? https://en.wikipedia.org/wiki/Hand_warmer https://en.wikipedia.

What about hand warmers? If you had one hanging inside a bottle would it use up all the oxygen? https://en.wikipedia.org/wiki/Hand_warmer https://en.wikipedia.org/wiki/Hand_warmer > Air-activated hand warmers contain cellulose, iron, activated carbon, vermiculite (which holds water) and salt and produce heat from the exothermic oxidation of iron when exposed to air. They typically emit heat for 1 to 10 hours, it usually takes 15-30 minutes to start to heat up, although the heat given off rapidly diminishes after 1–2 hours.[5][6] The oxygen molecules in the air react with iron, forming rust. Salt is often added to catalyze the process.