law: Indian Stamp Act, 1899 
  12. Cancellation of adhesive stamps
  (1) (a) Whoever affixes any adhesive stamp to any instrument
  
  chargeable with duty which has been executed by any person shall, when affixing
  
  such stamp, cancel the same so that it cannot be used again; and
  (b) Whoever executes any instrument on any
  
  paper bearing an adhesive stamp shall, at the time of execution, unless such
  
  stamp has been already cancelled in manner aforesaid, cancel the same so that
  
  it cannot be used again.
  (2) Any instrument bearing an adhesive stamp which has not been
  
  cancelled so that it cannot be used again, shall, so far as such stamp is
  
  concerned, be deemed to be unstamped.
  (3) The person required by sub-section (1) to cancel an adhesive
  
  stamp may cancel it by writing on or across the stamp his name or initials or
  
  the name or initials of his firm with the true date of his so writing, or in
  
  any other effectual manner.