Got a terracotta floor to clean (16 square metres) and the cust wants the grout colour changing. It currently has a floor polish on it by a company called Benton 'no buff floor polish' - just says contains polymer emulsion. The polish seems to come off with heavy duty tile and grout cleaner. Would it be worth using a 220 grit honing powder as the customer does not like the shiny look of the tiles at present. Once the tile and grout is clean do you have to wait until the grout is completely dry before applying grout colourant?