Format:
cast 'preservation' <object>            cost: 25 mana

   This spell is a high level cleric spell, which retards the decay of corpses
and some other types of organic matter.  While the spell is in effect, the
object will not decay, nor will be be edible by scavengers.  When the spell
wears off, decay will continue.

Note that it will not work on inorganic materials.