Coins are inconvenient to carry and transport due to their weight, so the smaller the denomination of the coin, the less popular it is.

When users sell foreign coins at discounts via the Coin birds app, foreign coins with smaller denominations require more discounts before they can be sold.

However, when travelers purchase foreign coins at a discount and bring them back to the issuing country, the purchasing power of these coins will jump back to their original denominations.

Therefore, we can use this feature to carry out risk-free arbitrage between currencies, denominations, and countries.

Outdated or Discontinued currencies

Some currencies that have ceased circulation, such as the currencies of EU member states before the euro was issued, can still be exchanged for euros at banks in the issuing countries.

Sometimes, currencies that have been discontinued have high collection value.


Because coins are mixed with a variety of metals and have complex compositions that make it difficult to refine, foreign currencies will eventually become garbage over time. If the Coin birds app users reach a scale, this situation can be changed and foreign currencies can be returned to the country of issue and used again.