Be careful, the BATFE isn't going to be happy with you possessing what might be considered by them to be an unregistered destructive device. How do you get something like this thing safely (and legally) deactivated?
I didn't even think about that at the time. You're right, of course - owning an explosive device is illegal. When I discovered the grenade was live my first thought was to get rid of the explosives. I'd done so many dangerous things already that carefully pouring and washing out the main charge seemed like a piece of cake. Then I disposed of the explosives as safely as I could think of. The dangerous stuff is all gone now and the grenade is absolutely empty. Just an inert piece of cast iron. So I'm not really a person of interest to anyone unless you're interested in some scrap iron.
In hindsight, I should've called the EOD and they'd probably end up destroying the thing. I don't think any EOD guy would even attempt to deactivate an old hand grenade. Not worth the trouble, I guess - not that I blame them. They just tend to take away the stuff and blow it up some place safe so that nobody gets hurt.