The curative aspect of conservation of records involves the treatment of brittle, fragile and acidic records of permanent value so as to minimize and mitigate the deterioration of the documentary heritage stored in this department using a process called de-acidification. The process involves the use of alkaline chemicals such as calcium hydroxide and calcium bicarbonate to remove the acidity present in the documents. This is called aqueous de-acidification technique and is widely used in National Archives of India to remove acidity and to strengthen the records so that the documents of historical value are preserved for posterity. The documents which are written on water soluble inks are de-acidified using a non-aqueous method.