There is a 2nd level spell available to every casting class except for Bard that reduces energy damage of a choice by 10 for at least 30 minutes. This would more then negate a Flaming, Shocking, Corrosive, or Frost weapon but would have no effect on an Impact weapon. Stopping energy damage is extremely easy whereas stopping slashing/piercing/bludgeoning or untyped damage is much harder, and nearly impossible once the almighty +1 is added to the weapon.
Even Sonic damage was so rare in the early editions that adding sonic damage to a weapon is nerfed, and this same spell can negate it as well.