A special
device which
crushes cremated remains into a fine
ash.
It is a little known fact that a cremation furnace (typically running at 700-1000 deg. C) is not hot enough to completely break down a human body. Very often a substantial portion of the skeleton stays intact in the furnace, thus before the remains can be interred or scattered they must be placed in a cremulator and pounded into a homogenous grey ash.
As a side note: The fact that intense heat alone cannot completely oxidize the human body is considered strong evidence against the existence of spontaneous human combustion.