You know that iron rusts, but when you grow up and are very very wise you will not say that iron rusts. You will say it become oxidized. This means that oxygen of the air burns the surface of the iron. Rust is really an iron ash. You can rub old rust off in a powder as fine as ashes.
Rusting spoils the appearance of cars and buildings and the damage it causes costs a lot of money to be set right. However, did you know that rust is actually beneficial to us in many ways.
Rust, mixes with the soil, giving it its good brown or red colour. Powdered rust dissolves in water, is taken up by plants and used to make their green colour. Finally, though water and plants, we taken iron into our bodies to give us the red colour of our blood. So you see, rust is really useful and though gold and silver are more beautiful and do not rust, they are not as essential to us as iron!
