World Coin

Both from Thailand, 5 satang, 1950 - although they were also made until 1973 with this "frozen" date. They are made of tin, which is pretty rare - if this coin's temperature dropped below 13.2 Celsius (56 Fahrenheit) it would begin to slowly crumble into tin powder, having been affected by the dreaded "tin pest" (where tin metal changes its atomic structure below a certain temperature). Luckily, the average low temperature in Bangkok in December is 22 Celsius.

These are bronze and that is ok, I live in the Pennsylvania and it gets colder that that here, with wind chill we see -40 to -50 below here in dead winter.