Don't leave food in cast iron overnight.

No, you shouldn’t.

The biggest risk isn’t rust—though that’s possible if the food is acidic (tomatoes, wine, citrus) and eats through the seasoning, leaving bare iron exposed. Overnight is plenty of time for that reaction to start. Even non-acidic food can trap moisture against the seasoning and cause tiny rust spots if your pan isn’t perfectly seasoned.

Off-flavors are real too. Cooked food sitting in a cast iron pan can pick up a metallic taste, especially leftovers that are slightly acidic. The iron leaches into the food. It’s subtle but noticeable the next day.

And honestly, it’s just lazy. Cast iron cleans up in two minutes—hot water, stiff brush, dry on the stove. Leaving food in it overnight means you’re letting the pan sit dirty and risking damage. Not worth it.

Clean it, oil it, put it away. Future you will be grateful.