I don’t know how you have been cleaning a burnt iron. But whether your iron got burnt with a cloth or not, using it for a long time without adequate cleaning would definitely change its surface.

They accused her of infidelity, beat her, burned her with an iron, and inserted chili powder into her genitals. She was later abandoned at a dam but found by a passerby and hospitalized.

There may well be some iron inside each burnt strand, but it can’t react because no oxygen can get to it there. This effect of surface area effect is actually a very general principle.