Long burial of objects leads to the formation of calcareous accretions on the objects. These accretions cover the object and hide their ornamentals details. Old copper objects also develop a bluish green patina on them, which enhances the aesthetic value of the objects. Calcareous accretions generally cover the patina and sometimes they get ingrained into the patina. The calcareous deposits on the objects are unwanted and should be removed whereas the bluish green patina should be protected. The methods used for the removal of calcareous deposits were either inefficient or damaging to the patina. Mechanical cleaning is arduous in case of stubborn accretions and not suitable for accretions ingrained in the patina. Sodium hexametaphosphate (Calgon) has been in use for this purpose for a long time, but it damages the bluish green patina of the objects. NRLC developed a method to remove stubborn calcareous accretions from copper objects without affecting the patina. The method employs sodium tripolyphosphate (STPP) as the reagent. The results of the studies have been published in Studies in Conservation, 39,39-44 (1994)