Don't count on oil to deactivate it.
Put on your safety glasses and use an inertia bullet bullet to remove the bullet making sure the primer isn't pointed at anything important while swinging the thing. (I'd just go outside and bang it on something.) Once the bullet and powder is out run the case slowly through your sizing or universal depriming die. Save the primer if you want to reuse for range/practice ammo as long as the anvil is still in it.
Or just toss the whole thing in the dud bucket at the range...
Proud member of the NRA and Texas State Rifle Association. Registered and active voter.