Sometimes the design of banknotes issued is changed by governments and new signs, inscriptions, holes, stamps are appeared on its. When new inscription is printed on the banknote it is called overprint. Overprints are widely used all over the world. For example, in 1985, after denomination Argentinian peso got new name - austral. Consequently a huge amount of banknotes issued in old units were put in circulation with overprints indicating new face value in austral and new name.
Overprinted Argentinean banknote
Overprints were issued several times by the government of Brazil. At first time it happened in 1966-1967 because of denomination of national currency cruzeiro. After denomination old banknotes remained on hand but were marked with round stamps pointing out new face value. Lately this scenario was repeated several times. In 1986 when currency was renamed crusago, in 1989 when another denomination happened and in 1991 when the old name cruseiro was returned to brazilian currency.
Cruseiro banknote with overprint
Sometimes instead of overprints a perforation is used. New figures and letters on the banknotes appear as a result of punching holes on its. It took place in the North Russia after revolution because of total shortage of everything including paper. On the picture you can see a paper money perforated at the top - "ГБСО" (Государственный Банк Северной Области - State Bank of Northern Areas).
Perforated 5 rubles banknote of North Russia
Instead of overprints it is also possible to use marks sticking on banknote’s surface. Marks have its own picture, perforation and point out new face value. Marked banknotes were used in Hungary, Czechoslovakia and China. The recent example is so called "suvorovki" - currency of Transdniestria. After USSR collapse the government of Transdniestria had to reserve soviet rubles in circulation. But for protection its economy from out of use banknotes from former Soviet republics they decided to mark Transdniestria currency with a portrait of famous general Suvorov.
Suvorovka - marked currency of Transdniestria
Another type of corrected banknotes contains typeovers when black masks or special ornaments spreaded manually or typographically are covered inscriptions, signs, symbols disliked by officials. One of the examples is banknote of Islamic republic of Iran after revolution in 1979. The portrait of overthrown shah was typeovered with black lines and arabesque ornament:
Typeovered iranian banknote