A specimen stamp is a postage stamp or postal stationery indicium sent to postmasters and postal administrations so that they are able to identify valid stamps and to avoid forgeries.[1] The usual method of invalidating the stamps is either overprinting in ink or perforating the word Specimen[2] across the stamp and where English is not the common language, the words Muestra (Spanish), Monster (Dutch), Muster (German) or Образец (Russian, 'Obrasetz') have been used instead.[3]