Corrode

3rd level transmutation (Bard, Cleric, Druid, Sorcerer, Warlock, Wizard)
  Casting Time: 1 action
  Range: Touch
  Components: V, S
  Duration: Instantaneous
  You target an non-magical object in range, If the object isn't being worn or carried, the touch destroys a 1 foot cube of it. If the object is being worn or carried by a creature, the creature can make a Dexterity saving throw to avoid the spell. On a fail, If the object targeted is either metal armor or a metal shield being worn or carried, its takes a permanent and cumulative -2 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. A weapon takes a permanent and cumulative -2 penalty to damage rolls. If its penalty drops to -4, the weapon is destroyed.