There wasn’t an efficient or thorough method of cleaning tile and grout prior to the Hydro-Force Hard Floor System. As a result, tile and grout surfaces, having been mopped for years, are in great need of restorative cleaning(s). One thorough cleaning after 10 years of neglect may not return the surface to the desired level of restoration. Always do a cleaning test to determine effectiveness and allow the customer to decide. If the result is not perfect, advise the customer that several thorough cleanings may be necessary to overcome years of poor maintenance. You might want to recommend color sealing the grout to restore it to an even appearance.