Mysterious safe

I've got this metal-box for ages. Once bought it on a flee-market almost for free because it had no key anymore.
Back at home, I managed to open it with some old worn-out keys my parents had laying around, only to find the original key to be inside ;)

Now I save my old coins in it... well old... not really. Only the worthless coins left in my wallet after visiting a country.
I've even got a 1-cent coin from Korea from last may. The value... 10000 Won is about 8 euro.
Also some paper-work, like 20 Belgium-Franks, 300 Albanian-Lek and a few Dutch coins for good memory.