Section 12 of The Kerala Stamp Act, 1959 (No.17 of 1959) View Chapter 2

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 sub­section (1) to cancel an adhesive stamp may cancel it y writing on or across the stamp his name or initials or the name or initials or his firm with the true date of his so writing or in any other effectual manner.