Internally the deterioration had led to separation of several of the case iron columns from the walls and many of the etched glass panes were broken. Electrical cables were conspicuous all over the building. Poor lighting created a dull and gloomy atmosphere. It’s richly coloured interiors and exquisite details had also been effaced, and a yellowing off-white paint had brushed away the gold gilding, the refined design details and with it the vision and intentions of its founding fathers. All this and more had to be addressed in the Museum’s restoration. Colour and details had been effaced from the building which had been painted a yellowing off-white. Paint was scraped till the original colour layer was established. Scrape samples of paint were tested in INTACH's Delhi laboratory to determine the colour accuracy of the original paint finishes. Research was done to ensure that the modifications which were necessary remained within the Victorian Palatte and "celadon green" was finally decided to be used.
The squares and circles in the arched ceiling of the lofty central vestibule had lost their gilding and become dark and discoloured. The tympanum earlier had delicate fresco paintings which had been erased with paint and were not possible to retrieve.
The beautiful etched glass windows with specially designed grills and wooden louvers to protect the objects from the sun are a dominant feature of the building.