Never, ever play around with old ordnance. Some folks may have been raised with a gun in their hand, but very few with ordnance in hand.
I remember an older fellow who bought a grenade at a garage sale here in Tucson. He was driving back to his place when he realized that it was smoking in the bed of his pick up truck. Without thinking or a moment's hesitation, he pulled into a gas station on Grant and 1st to use the pay phone to call 911. To make a long story short, the TPD had to detonate it.
You might think it's safe, but can you really determine that without blowing yourself to kingdom come?