The Secretary is authorized to permit public and private agencies, corporations, associations, organizations, or individuals to use any real property, or any facilities, structures, or other improvements thereon, under the custody and control of the Secretary for Department purposes. The Secretary shall permit the use of such property, facilities, structures, or improvements under such terms and rates and for such period as may be in the public interest, except that the periods of such uses may not exceed five years. The Secretary may require permittees under this section to recondition and maintain, at their own expense, the real property, facilities, structures, and improvements used by such permittees to a standard satisfactory to the Secretary. This subsection shall not apply to excess property as defined in section
102
(3) of title
40.