Obviously the bodies were recovered at the time, but the aircraft wreckage was in a particularly inaccessible place and the bulk of it was left behind. Thirty years later, in the 1980s, the National Park Authority asked United and TWA to remove it and there was a substantial operation to do so, aided of course by the developments in helicopter technology in the intervening years. However, one of the linked articles shows that the clear-up was obviously not quite complete.