How would do you safely destroy a megatall?

Aside from the World Trade Center towers in New York City, there has been (to my knowledge) no other destruction of a modern supertall in the world, at least to my knowledge. We can only assume that architects aren't all designing these buildings to last 500 years (basically until lasers and evaporating rays can do the job ). So if there ever becomes a need to raze these buildings, either to build new ones or because the old ones have become too dangerous or old to use, how would it be done?

The WTC showed us how an uncontrolled destruction could leave layers of dust around the entire city, and also collaspe nearby buildings as well. Even if you could remove as much material as possible from each building before you tried to destory them, for buildings over 50 stories in height, there's still a lot of material to get rid of. If it were imploded using explosives, I couldn't imagine there being a good barrier against materials destroying nearby buildings, especially in a busy urban center. So how would it be done?>