How it is preserved
ASI started using fuller's earth with a mixture of aluminium silicate and magnesium trisilicate to remove tarry/greasy particulate matter in 1984. Today, ASI claims it has stopped using harmful chemicals and only adds glycerol, cellosolve and sodium bicarbonate to the mud pack in summers to ensure that it does not dry out fast.
An alkaline solution of ammonia is used to clean the red sandstone. ASI uses a special biocidal treatment for the sandstone portions that are hidden from sun and gather moss and algae because of humidity. Preservatives are also used to increase the longevity of the stone.
Stones of the inlay work are replaced if they get damaged or broken. Earlier, artisans were chosen through a tender system. The process was discontinued after it drew criticism because the lowest cost did not assure quality work. ASI now hires artisans based on their craftsmanship, but still has no guidelines for hiring them.
Sandstone floors are in a more precarious condition than the marble floors because of their high porosity that locks moisture inside. As a result, the red sandstone floors are chipping at many places. ASI has put barricades near the Mehman Khana to stop visitors from stepping on them.
Wooden stairs have been added to decrease the pressure on marble floors and staircases and avoid wear and tear. The monument was constructed to take the weight of 30-40 people at a time. Today, over 10 million tourists visit it annually and the footfall is wearing out the walkways of its garden and the floors of its terraces.