Granite needs to be cleaned regularly to maintain its natural sheen and vitality. We suggest that you clean stone surfaces with an ammonia mix. (5/1000 parts anomia and water).
Alternatively, you can use a non-acidic soap-scum remover, mild liquid dishwashing detergent or denatured alcohol. There are also proprietary products available specifically for cleaning natural stone. These cleaners will remove oil stains and organic residues, returning the original sheen and colour to your flooring.