Iron golems rust in multiple stages, like iron items, rather than all at once. Each stage cuts its maximum HP by 20 (so a rusty golem has 60 max HP, etc.) Applying a can of grease will remove the rust and restore its max HP to normal, and may prevent further water damage for a little while. The golem may also quaff a potion of oil, which has a similar effect, except it also restores current HP as well as maximum by the amount of erosion removed.

Iron golems that rust to death may rarely leave behind a statue (ideally made of iron material) which is implied to be its rusted husk.

In a lot of folklore, iron wards away elves. This could be implemented in the game in several ways:

• Elves take extra damage when hit by iron. Not as much as silver, but still appreciable.
• Elven players take a small amount of damage when putting on or wielding iron gear, but get no further penalty. (dnethack hurts their regeneration rate while wearing iron, which is another option).
• Possibly some detrimental effect when wielding iron weapons as well, a to-hit or damage penalty, or negating bonuses from dexterity, strength, and skill, or something.
• This is balanced by elven racial equipment being better (not improved; it’s already better).

It’s harder to force the lock on chests or large boxes made of metal, and increases the chance your weapon breaks. Additionally, the material of the weapon used to force the lock affects the result, if it’s used to pry rather than bash:

• Iron and metal behave as normal.
• Mithril is stronger than iron, and breaks less.
• Copper is slightly weaker than iron, and breaks a little more often.
• Softer metals, such as silver and gold, break less often but tend to bend. A “bent” weapon doesn’t actually become bent internally; it just loses a lot of enchantment.
• Wood is about as good as copper.
• Glass almost always breaks, and can break even if used to bash open a lock.

If you are wearing iron shoes, you cannot be forcibly knocked back to other spaces, unless you are levitating.

Rubbing iron on a flint stone gives the message “Sparks fly from the stone”.

Iron and copper items engulfed by gelatinous cubes get corroded in the process.