The character corrodes iron and iron alloys at a touch. Any iron or iron alloy item the character touches becomes instantaneously rusted, pitted, and worthless, effectively destroyed. If the item is so large that it cannot fit within a 3-foot radius (a large iron door or a wall of iron), a 3-foot-radius volume of the metal is rusted and destroyed. Magical metal items are immune to this spell.
The character may employ rusting grasp in combat with a successful melee touch attack. Rusting grasp used in this way instantaneously destroys 1d6 points of Armor Class gained from metal armor (up to the maximum amount of protection the armor offered) through corrosion. For example, full plate armor (AC +8) could be reduced to +7 or as low as +2 in protection, depending on the die roll.
Weapons in use by an opponent targeted by the spell are more difficult to grasp. The character must succeed at a melee touch attack against the weapon. A metal weapon that is hit is instantaneously destroyed. Note: Striking at an opponent’s weapon provokes an attack of opportunity. Also, the character must touch the weapon and not the other way around.
Against ferrous creatures, rusting grasp instantaneously deals 3d6 points of damage +1 per caster level (maximum +15) per successful attack. The spell lasts for 1 round per level, and the character can make one melee touch attack per round.