The transmute metal to wood spell enables the caster to change an object from metal to wood. The volume of metal cannot exceed a maximum weight of 10 pounds per experience level of the priest. Magical objects made of metal are 90% resistant to the spell, and those on the person of a creature receive the creature's saving throw as well. Artifacts and relics cannot be transmuted. Note that only a wish spell or similar magic can restore a transmuted object to its metallic state. Otherwise, for example, a metal door changed to wood would be forevermore a wooden door.
Notes: Common for druids (PHB).