[Semis]

Adamantine Golems aren't so tough - most of the time. You can use its size against it. In the thin passages of most dungeons, they can't approach you to attack. If you have Lower Magic Resistance, you can open it up to spells. Or, even better, their attack range is shorter than a staff or two handed sword. You can safely whittle it down from just beyond arm's reach. Sometimes their poison cloud gets you, but that's easily treatable with a couple Slow Poisons on hand. A little time consuming, maybe, but a relatively free 25000 xp.

Of course, if they're not restrained by corridors, it's another matter entirely...