Can anyone please offer me some advice? I have just purchased some Black Granite Quartz tiles which were hugely expensive, they came in their boxes with an individual cellophane protective sheet on top of each tile. When I have removed the cellophane it has left a mark on each tile similar to a water mark which I have tried to remove with water, fairy liquid and a bit of elbow power. It doesnt seem to have worked. The supplier recommended I use some sort of Marble or Granite polish, will this work? And what is the best one to buy? Thanks in advance.