hi guys, been asked to quote a shop front. the shop has marble pillars and surround around the windows. he wants the marble jet washed as when you rub your finger along it dirt comes off although it does not look really dirty. its just a film of dirt. should i use just low pressure or apply a non caustic tfr to shift it? will this affect the marble? i think it should be ok to apply tfr as long as i was it off. thanks.
