3,191. Money is Fungible

Hilchos Matnos Aniyim 8:4

Regardless of whether one says, “This coin is charity” or says, “I commit a coin to charity” and puts it aside, he is permitted to exchange it for a different coin. Once the money is in the hands of the charity administrators, it may no longer be exchanged. If administrators want to have the money changed, they may not do so (in order to avoid the suspicion of profiting on the exchange rate). If there are no needy available to receive the funds, the administrators must have others exchange the money for them rather than doing it themselves.

Hilchos Matnos Aniyim 8:5

If the needy would benefit from the charity administrators not distributing the money right away, as this might motivate others to donate, then they may borrow these funds and repay them when needed. This is because money for charity isn’t like money committed to the Temple, from which benefit is prohibited.