If you'll remember, a few years ago, I told my oldest son about US junk silver, telling him that quarters, dimes, and half dollars 1964 and before were 90% silver. He proceeded to go through his saved change and find two silver dimes. Incredible luck! In the US you might come across junk silver in the wild every now and then, but we aren't in the US. Yet from the limited US change he has collected over the years, he found some!
Well, his luck hit again. He came home from the gamecenter and with a giant grin, showed me another silver dime.
He said it was in one of the game coin slots. All games take ¥100 coins here, so why a dime ended up in one... I suppose maybe a parent watching his kids dropped it, then a kid picked it up and decided to try using it in the machine to get a free game. I doubt very many Japanese kids, my own aside, have any awareness at all about dates to look for in dimes.
So another lucky find!
I know, it's only worth around $2.50, so we're not talking about a lottery win here. But still, he's found three of them now, and in a different country — what do you suppose the odds are?

Just in case anyone reading this isn't aware: many countries used to use silver in their coins, back before inflation made governments decide that was a bad idea. The US was no exception. For most of their history, dimes (10 cents), quarters (25 cents), and half-dollars were composed of 90% silver. But then in 1965, the value of silver just got too high and so the mint switched to cupronickel-clad (copper-nickel) composition. Half dollars held out a little longer. They were dropped to 40% silver and then then too switched entirely to cupronickel in the 1970s.
So yeah, if you do have any of these three coins, check the dates! You might be lucky like my son.