When this approach isn’t viable, and unless the site has some heritage value, the most viable solution may be to make way for new construction.
In the event that Venezuelan officials opt to demolish the Tower of David, the rubble can be recycled and remade into new materials. Should they choose to build an entirely new skyscraper over the site, they can do so with these new materials. In the same manner, a company that recycles scrap metal for pick up—such as Global Resources International Pty Ltd, for instance—can help clients save on the cost of building a new structure.
http://www.globalresources.net.au/high-quality-scrap-metal-pick-new-hope-amid-rubble/
Global Resources International Pty Ltd 