The earth shakes briefly in Berlin's Mittelheide city park, and a cloud of rain-soaked dirt rises in the woods. Police have just detonated a football-size antitank grenade from World War II.

More than 60 years after the war's end, removing unexploded bombs, grenades and artillery shells remains a full-time task for police and private companies across Germany.

It's an occurrence so common that police explosives experts Thomas Mehlhorn and Joerg Neumann can joke about their delicate job as they sift warm pieces of shrapnel from wet dirt reeking of sulfur.

"When the weather isn't as bad as it is today, of course this job is fun," Mehlhorn said.