The whole ground floor of our French house has beautiful, porous terracotta tiles, most of which have a lovely glaze. Unfortunately, in the five years we've owned the house we've suffered damp on the surface of the tiles in one end of the lounge (it’s not a good idea to leave wet washing in a closed up house). We also had a minor leak in the bathroom - drips from a faulty washer, (we normally turn the water off but were expecting a builder to begin work) and now the beautiful tiles aren't so beautiful in places. The lovely glaze has worn away in patches of the lounge where attacked by saltpetre and the ones affected by the leak are limed (white in patches) and dark stained in the worst places where they went mouldy. I've tried all sorts of stuff for terracotta from Weldom (Starwax stain remover for terracotta etc.) but nothing to show for my huge effort. Does anyone know if there are companies that will restore the shine to your floors or are there any products that will work where Weldom's have failed? Should I use one of those hand held sanding machines or would that ruin them altogether? Advice appreciated