removing grout from slate floor

[I'llfinishlater]

Can somebody please help me. I have just had a slate floor laid in my kitchen. Despite me going on and on to the tiler not to get grout on the slate I came home to find it covered in grout and sealed!!! He tried to remove it with some sort of acid, but although it's better there is still loads of grout stuck in the crevices. He has now given up! I have tried white vinegar which seems to work quite well at getting the really heavy stuff off, but then leaves a white haze. Our whole kitchen has been piled up in another room for a month now. We are all getting a bit fed up of salads and washing the dishes in the bath is no joy! Hoping somebody can help

Thanks in anticipation Julia

 

[gcol]

Have a look at this:
http://www.aldonchem.com/popup-ab-grout-residue.htm
I haven't used their products though.