The Wand of Cloudkill is just about the only AOE spell that works on golems. Breach or Spell Thrust won't do anything as they're not protected by spells but by natural MR which is very high. Your best bet would be to cast Lower Resistance a few times, then Greater Malison, then an instant kill spell like Finger of Death (or anything that will force them to make a saving throw).
Evocation spells like magic missile, flame arrow etc are fairly useless against them.
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Memnoch - Custodian of the Order of the Holy Flame 