Common Good Credits have value and act like money because we agree to accept them as payment for our good and services, so they move from member to member to member as a token of exchange. When someone pays you in Common Good Credits, you can spend those funds — OR you can "cash them out" by transferring them to your bank account or exchanging them for US Dollars.
You can cash out Common Good Credits that someone pays you, but any Common Good Credits you borrow from your Credit Reserve must continue to circulate within the Common Good system. You cannot cash them out — you can only spend them.
You can help keep the Common Good system healthy by maintaining a positive balance most of the time.