Following the acquisition by the Federal Government of properties pursuant to this subchapter and until such time as the buildings thereon are demolished or the properties and buildings thereon are devoted to purposes of the Independence National Historical Park as provided herein, the Secretary is authorized, with respect to the said properties, to administer, operate, manage, lease, and maintain such properties, and lease, demolish, or remove buildings, or space in buildings thereon, in such manner as he shall consider to be in the public interest. Any funds received from leasing the said properties, buildings thereon, or space in buildings thereon, shall be deposited to the credit of a special receipt account and expended for purposes of operating, maintaining, and managing the said properties and demolishing or removing the buildings thereon. The Secretary, in his discretion and notwithstanding other requirements of law, may exercise and carry out the functions authorized herein by entering into agreements or contracts with public or private agencies, corporations, or persons, upon such terms and conditions as he deems to be appropriate in carrying out the purposes of this subchapter.