Iron is the least fussy cookware there is, as long as you understand one thing: the non-stick surface is a layer of polymerised oil that you build, not a coating that was applied at the factory and slowly wears out. You cannot use it up. You can only forget to maintain it, and that is reversible in an afternoon.
After every cook
- Clean it while it's still warm. Hot water and a chainmail scrubber takes off anything stuck without touching the seasoning underneath.
- A little dish soap is fine. The "never use soap" rule dates from when soap contained lye; it doesn't any more.
- Dry it on the burner, not on a rack. Two minutes over low heat drives out the water that would otherwise sit in the pores and rust it. This is the single step that matters most.
- While it's still warm, wipe a thin film of seasoning wax or any neutral oil over the cook surface and buff it until it looks dry, not greasy. A visible slick of oil goes sticky; a buffed film goes hard and slick.
Building seasoning from bare
- Wash and dry the pan completely.
- Wipe a very thin layer of wax or high-smoke-point oil over every surface, inside and out.
- Buff it back off until it looks like you missed. Too much oil is the number one cause of a sticky, patchy finish.
- Bake upside down at 450°F / 230°C for one hour. Let it cool in the oven.
- Repeat two or three times. Then cook something fatty in it and let cooking do the rest.
Rust
Not a crisis. Scrub it back to grey metal with steel wool or a chainmail scrubber, wash, dry thoroughly on the burner, and re-season as above. A pan that looks written off usually isn't — send us a photo before you throw anything away.
Carbon steel specifically
Carbon steel seasons faster than cast iron and colours as it goes — blues, bronzes and browns appear in the first few cooks and the pattern is never even. That is the metal telling you where it got hot. It is not damage and it will darken to near-black over a few months.
Be careful with long simmers of tomato, wine or vinegar in a young pan; acid strips young seasoning. Once the layer is mature it stops mattering.
Wood boards
Hand wash, never submerge, never a dishwasher — a dishwasher will split an end-grain board within a few cycles. Oil it monthly with a food-safe mineral oil or board wax, more often if it starts looking pale and dry.
Storage
Dry, with air around it. If you stack pans, put a sheet of paper towel between them so the rims don't grind the seasoning off each other. A wall rail solves this properly and puts the pan where you can reach it.