law: Indian Post Office Act, 1898 
  39. Final disposal of undelivered postal articles 
  Undelivered postal
  
  articles which cannot be disposed of under the foregoing provisions, shall be
  
  detained in the office of the Post Master General for such further period (if
  
  any), and shall be dealt with in such manner, as the Central Government may, by
  
  rule, direct:
  Provided that-
  (a) letters and
  
  postcards shall be destroyed;
  (b) money or saleable
  
  property, not being of a perishable nature, found in any undelivered postal
  
  article, shall be detained for a period of one year in the office of the Post
  
  Master General, and, if on the expiration of that period no person has
  
  established his right thereto, shall, if money, be credited to the Post Office,
  
  and, if saleable property, be sold, the sale-proceeds being credited to the
  
  Post Office.