Contractor didn't clean dust that had been tracked in on charcoal grout prior to sealing it.(I know this because I called to his attention that the charcoal grout didn;t look charcoal anymore. He said "oh that dust will clean out. Then I will seal it.") Now the color is definitely not charcoal in the traffic areas; in the corners where no one walked it is charcoal. What can I do to get the charcoal color back? Can sealant be removed enough to clean out the dust and restore the charcoal color? It totally ruins the look of the floor and takes away from the overall impression. One photo chows dark grout in no traffic area. Other shows the inconsistent grout shade across 98% of the floor.