On 18 October 1946, the ashes of the Nazi criminals, executed in accordance with the decision of the International Military Tribunal, were scattered.

After the execution, the bodies of the Nazi criminals were examined and photographed by representatives of the allied powers. Each body was wrapped in a prison mattress with clothes and a rope on which the criminals were hanged, and the bodies were placed in coffins. The same was done with the body of Göring who committed suicide. At 4 a.m. the coffins were loaded onto trucks, covered with a tarp and brought to Munich. According to an official communiqué signed by the Allies: "The body of Hermann Göring along with the bodies of other criminals executed by the verdict of the International Military Tribunal on 16 October, have been burned, and their ashes were secretly scattered to the wind".

The place where the ashes had been scattered was withheld in order to prevent the Nazis from turning it into a place of worship. According to one very dubious version, the ashes were allegedly brought from the crematorium to a building belonging to American troops, named "Morgue No. 1" - without specifying its location. And on the evening of 18 October, American soldiers cordoned off the area around the Marienklausen Bridge over the Isar River and the Isar Canal, and around midnight the mixed ashes were slowly poured from the bridge into the canal.

According to the official version, which seems quite reliable, the ashes were scattered from a plane in an unspecified place.

Source: 

Arkady Poltorak. Nuremberg epilogue / The introduction by Lev Smirnov. - M.: Military Publishing, 1965.