Gifts, bequests, or devises of money and proceeds from sales of other property received as gifts, bequests, or devises shall be deposited in the Treasury and shall be available for disbursement upon order of the Chairperson. (5) Mails The Commission may use the United States mails in the same manner and under the same conditions as other departments and agencies of the United States. (6) Administrative Support Services (A) General Services Upon the request of the Commission, the Administrator of General Services shall provide to the Commission, on a reimbursable basis, the administrative support services necessary for the Commission to carry out its responsibilities under this Act. (B) Additional support The Commission may accept additional assistance from any department or agency of the United States. (7) Subpoena Power (A) In general The Commission may issue subpoenas requiring the attendance and testimony of witnesses and the production of any evidence relating to any matter which the Commission is empowered to investigate by subsection (b). (B) Issuance of subpoena A subpoena of a witness or evidence shall be issued only upon if agreement is reached that such subpoena should be issued by— (i) the Chairperson and Vice Chairperson