Our current monetary system displays major flaws as to whether it can support the ecological turn. This article stylises them as bank credit, a-territoriality and non-specialisation of money, and commensurability. Yet, the variety of experiences of alternative currencies displays remarkable features like territorialisation, socio-economic specialisation of money, a practical criticism of commensurability and non-bank funding and financing schemes. Considering those features seriously, and making them part of monetary systems, require adapting the existing monetary infrastructure by creating specific circuits through the establishment of boundaries.