Starting when the first coins were struck, people have tried to counterfeit these coins. Counterfeiting is done in lots of ways, some are mentioned below:

• replacing precious metals (gold, silver) by common cheaper metals
• changing the percentage of gold or silver coins
• peeling of coins
• issueing coins at a higher exchange rate then the gold/silver contence justifies

Description	Obverse	Reverse
2.5 Guilder 1840 Willem I Copper coin with a very thin layer of silver, probably applied electrolitical.
2.5 Guilder 1863 Willem III Copper coin with a very thin layer of silver, probably applied electrolitical.
2.5 Guilder 1898 Wilhelmina Copper coin, the copper is removed from the surface by diping it into acid.
3 Guilder 1820 Willem I Copper coin, the copper is removed from the surface by diping it into acid.