Remove Scratches on Mag Wheels

[BYE911]

I recently bought a second hand astra convertible for my wife and only noticed on the weekend when washing the wheels that every one of them has light scratch marks on them like someone has used sand paper or a scourer pad to clean the wheels at some time.The front wheels particularily attract a huge amount of brake dust and i believe the previous owner has taken the easiest way out to clean them.
Any thoughts or suggestions on how to get these scratches out?