1. Expectations of what to do in these situations should have been negotiated when Spain agreed to let US fly nuclear armed airplanes in their airspace.

2. The Spanish government is currently renting the land from it's owners. I am very curious about the rent, as this land is currently useless. I don't know the details of Spanish law, but on the face this seems like a good case for eminent domain.

3. At this point, the cleanup process would involve moving dirt that contains trace amounts of radioactive material. This has been done before, but I think this would be both the largest effort and the one in which the dirt traveled the furthest (from Spain to the US, probably to a facility west of the Mississippi River.

4. Once the topsoil is removed, then what? Replace it with top soil harvested from someplace else? Start a project to restore the topsoil with lots of compost? It'll take another sixty years.

EDIT: This type of cleanup is an ideal use case for robotics, and I would love to see what technology they use to perform the cleanup. I imagine several semi-autonomous remote controlled tractor sized machines loading into containment boxes made of nine inch thick steel.