keep it in your jacket to warm it up 放在你的夹克里热
sleep with it in your bag 睡觉的时候放在睡袋里
place or dip it in warm water 放或者摁在热水里
pour a bit of hot water on it 倒点热水在上
urinate on your stove 在上面小便(汗一个)
chemical hand-warmers may help a little 这个意思是 用手来温
Risky methods of warming fuel canisters - using heat from a stove - overzealousness and carelessness can lead to an explosion - do so at your own risk 有危险的办法
use a carefully ventilated windscreen (if you do too good of a job insulating the canister, it may explode) 风挡挡严实
use a heat exchanger (flattened copper wire with one end wrapped around the canister once and with the other end protruding up into or near the flame) 热导装置
warm a canister by placing it near the stove (too close for too long and you might end up dead or without one of your hands)
Note - most canisters are designed with concave bottom that will pop outwards before complete canister rupture if over pressurized. The valves themselves may also bleed off overly pressurized gasses unless a stove or lantern is securely attached to it.
Another method to maximize fuel pressures is to feed your stove with liquid instead of gas fuel. This will allow the vapor pressure of the more volatile fuels to force mixed liquid fuel into your stove instead of just burning up first and leaving unusable butane. There will also be less phase change from liquid to gas in the canister resulting in less canister cooling. This concept is used with the Coleman PowerMax fuel canisters, which have a weighted diptube to pick up the liquid at the bottom of the can and not the gas at the top.