The secretary shall have the authority, in the name of the state, to enter into contracts with any duly authorized representative of the United States of America, or its territories, or other states for the provision of services under this title at the expense of the United States, its territories, or other states. The contracts may provide for the separate or joint maintenance, care, treatment, training, or education of persons. The contracts shall provide that all payments due to the state of Washington from the United States, its territories, or other states for services rendered under the contracts shall be paid to the department and transmitted to the state treasurer for deposit in the general fund.