My boyfriend grouted our Marble floors for the first time. Instead of wiping the grout up soon after you lay it down, he let it sit overnight. Our entire marble floor is covered with swirls of thin grout. We have been moping it with muriatic Acid and water but it doesn't seem to be coming up. Tonight I'm going to try scrubbing it with a brush along with the acid and water. Is there any product out there that is specifically to get grout up or does it have to be done manually like that way I'm doing it?