Quote Originally Posted by The_Emperor
You cannot do this with a rebellious city because when it revolts you get a rebel army turn up.

I did it once in carthage and a new Carthaginian army appeared in the city complete with War Elephants (and walls cannot be removed from a city to make it easier to take)... It was a nightmare retaking the place in order to exterminate again and reduce squalor and unrest.

Also often such an army cannot be bribed.
but you can still sell it and take it back, you don't have to hold a siege, there's no one in there.