Any weapon you want, but I think maces/clubs do more damage to skeletons than swords if I remember correctly. Also there is a cheesy tactic that can be abused to basically kill any enemy in there without them being able to hit you. but it's up to you if you want to make use of that or not. When you enter a dungeon the small entrance "platform" while you stand on it the enemy won't follow or attack you. So you can just go there while the enemy chases you and then shoot them with arrows from a save distance without them being able to reach you. But it's it's a little bit cheesy and too easy to do it this way.