I will admit that a collision with Mercury would do the job thoroughly, though if humanity is still around in a few billion years it is quite possible we will have the ability to do something about it.
Yeah, I’m not going to sweat it too much. Within one billion years the Earth will likely make contact (euphemism) with a plus-one-mile impactor, basically a piece of debris — and not just once, more than sixty times. And probably at least eight of those will be well over a mile in diameter.