Tuesday''s Ask the Experts question from a cleaning professional on the International Custodial Advisors Network (ICAN) "Ask the Experts" page: I have just taken over a new building with white 1-foot-square ceramic tile with black speck in it. The contractor did not clean the tile before turning over the building, leaving a red clay tint on it. I have autoscrubbed with a brush. It cleaned the grout, but left a light red tint. I have also hand-scrubbed tile with deck brush with little or no results. Any suggestion what type of cleaner to use, or any suggestion would be deeply appreciated.
First, make sure the client understands that this is not your problem and that there is an extra charge for this service. You will try to correct it, but it is not of your making.
Second, try to find the source of the tint. Does the grout have a red tint added? If so, you may have to do a light acid wash to break the film from the tile surface.
Use caution, hydrochloric acid is very corrosive to ...
— Lynn E. Krafft, ICAN/ATEX Associate Editor, firstname.lastname@example.org