Perfin

[2] The practice spread quickly to Belgium (1872); Denmark, France, Germany and Switzerland (1876); and Austria (1877); the U.S. finally allowed perfins in 1908.

[3] In Britain unused postage stamps could be redeemed for cash at the post office.

Formerly considered damaged and not worth collecting, perforated postage stamps are now highly sought after by specialist collectors.

Note that the block of 12 stamps illustrated on the right includes two copies of the highly sought-after erroneous 5-cent denomination instead of 2 cents.

[5] In addition to stamps, postal stationery envelopes, postcards,[6] and newspaper wrappers[7] were perfinned.

A 1951 perfin stamp of the UK (used by HMSO ) showing front (top) and reverse (bottom)
A postal stationery envelope used from London to Düsseldorf in 1900, with additional postage stamp perfinned "C & S" identifying the user as "Churchill & Sim" per the seal on the reverse shown on inset
An unusual curved perfin INVENTION from Patent Agents G.F. Redfern & Co. of London, whose telegraphic address was also INVENTION
A large block of United States perfin stamps
A 1955 Canadian stamp with a CPR (Canadian Pacific Railway) perfin