Try distilled white vinegar applied with a soft, clean rag, but try it on a small inconspicuous area.
Distilled white vinegar was recommended to me by Sal Zaino, the owner of Zaino showcar products, when I needed to remove some water spots from my black auto.
Distilled white vinegar was recommended to me by Sal Zaino, the owner of Zaino showcar products, when I needed to remove some water spots from my black auto.