Specimen stamp

[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.

Specimen stamps have no postal validity so postal administrations are free to distribute them as widely as they like and this can include to stamp dealers, philatelic magazines, government bodies, embassies and as promotional items for philatelists.

Inversely, many genuine specimens have had their overprints removed to make them resemble the much more expensive base stamps.

[citation needed] The use of specimen overprints is not restricted to postage stamps.

It has also been used on revenue stamps and postal stationery, including International Reply Coupons.