Preventing the concealment of stamps

Well, it can happen that stamps are put on the market in a way without the postal service in question earning any revenue from it. In 1882, this was possible in Brits Guiana happen, a British colony on the north coast of South America. Since 1966, it has been an independent republic with the name Guyana located between Suriname en VenezuelaTwo stamps were printed by Baldwin & Co, a printing house in Georgetown, the capital of British Guiana. Usually, stamps were printed by stamp printing houses in England, but due to a sudden shortage of stamps in the values ​​of 1 cent and 2 cents, stamps had to be printed locally. This had happened once before in 1856 when a shortage of 1-cent and 4-cent stamps arose. Newspaper printing house J. Baum & W. Dalles, also in Georgetown received the commission. The stamps featured a sailing ship. It was not until 1873 that the 1-cent stamp (domestic rate!) was discovered by chance by a young collector, and within a very short time it became a great rarity! In 1878, the stamp already fetched 120 pounds, a considerable sum at the time.      Thus, a few years after the rarest stamp in the world of philately (only one example of the 1 cent is known), a similar opportunity presented itself again. To prevent employees of the printing press and post offices from being tempted to conceal the stamps, a security measure was taken. A civil servant applied a perforation to every stamp in each sheet supplied by the printer; this perforation could only be performed by that civil servant. This was the civil servant who was also responsible for sending new stamps to the Universal Postal Union. He had at his disposal a perforator capable of perforating the word SPECIMEN into the stamps. The word SPECIMEN indicates that the stamp is in fact NOT valid for franking purposes, but is intended for, among others, the Universal Postal Union, the press, and so on. However, in this case, the stamp was the official issue only with the SPECIMEN perforation, and was indeed valid for franking!     Because the perforation was applied by hand, quite a few variations occur, such as from bottom left to top right, from bottom right to top left, and double-perforated. In total, 24 different variants of the 1 cent can be collected, and 36 different variants of the 2 cent. The fact that the measure did not entirely help is evident from the fact that stamps without the SPECIMEN perforation still appeared on the market. However, these stamps never achieved a very high collector's value. The 1 cent stamp of 1856 thus remains the rarest stamp in the world.