Hey abrakdabra, let me get back to your subject, which seems to be: "What's the quickest way to provide my life insurance money to my next of kin?" Well, I think you've found it. Arcomandpurple (where do you guys get those names?) is being too conservative when he says 100 years. I'm more inclined to think at least a thousand. But that will take a few years yet to prove.
Here's how the Civil War THer's do it when they dig up a live cannon round: No, I'm not going to tell you how. You'll just get in trouble. It takes experience, and neither you nor I have it. Instead, here's what you do if you find a live Civil War round: Take it to someone who does that sort of thing and pay him the few dollars he'll ask to do it for you. Then hie thee the hell out of the area until he calls and tells you to pick up your shell. Simple, no hastles, no risk (except in digging it up and carrying it around with you).
When I was a boy (I joined the Army at 17 and became a quad-.50 gunner. Go ahead, ask me if my ears ring now.), I made kind of a hobby out of taking live .50-caliber machine gun rounds and twisting them back and forth in a faucet head until they loosened and I could pull out the head and pour the powder out. I lived to tell the tale but might not have, and I wouldn't do it today. (And you can bet this is one army experience I haven't told my wife.)
Okay, what I did was very dangerous. Stupid, in fact. Yours is more so; much more so, if you're in the wrong area. You might not run across any shells, grenades or mines, but if it was me, I wouldn't take the chance. (Remember, a mine is meant to go off when touched. It might not wait for you to identify it first.)
Having said that, I'm going to partly reverse myself. There are probably areas of Korea that weren't within a hundred miles of the war. If you're in one of those, find out the chances of any old buried ordnance being anywhere nearby. Check with the police, historians or anyone else you can think of who would know. And check if there are any local THers that you can learn from. Then use your own judgement.
Good luck and stay out of trouble.
-Jim