hi, i had to remove the grout between tiles cause didn't like the colour. that created some small scratches on the tile surface. Then my builder grouted the whole area without asking me first. The tiles are gloss white, the grout grey. Unfortunately the small scratch areas are now filled with grey grout and i can't remove it with normal sand paper, not without scratching the tiles further. Can i use some chemical remover or what else can i do?. Before i could hardly notice the scratches but now they are so prominent. Thank you for any answers.