Bali Limestone

We have an extensive area of Limestone tiles (from Bali) as the flooring and some have not been sealed properly.  Olive oil has been spilt in a trail on the tiles and was not attended to straight away - some of the tiles are in the sunlight and the oil has soaked in.  We have tried many different cleaning options but none have worked.  Is there a solvent that can assist?  Your help and advice would be greatly appreciated.