Bluestone

Treat the surface with a stain-blocker for bluestone (protects against grease, but not against acids)
Clean daily with a damp cloth and a neutral washing-up liquid
Rub stubborn stains thoroughly with Cif Cream White on a damp sponge (do not rub in small circles; apply only to the stain)
Do not place hot pots directly on the worktop
Do not cut directly on the worktop
Be careful with acids and fats: they can cause stains