34 C.F.R. § 675.21
(a) An institution, other than a proprietary institution, may employ a student to work for the institution itself, including those operations, such as food service, cleaning, maintenance, or security, for which the institution contracts, if the contract specifies—
(b) A proprietary institution may employ a student to work for the institution, but only in jobs that—
(2) Are on campus and that—
(iii) Do not involve the solicitation of potential students to enroll at the proprietary institution.
(Authority: 42 U.S.C. 2753)
[52 FR 45770, Dec. 1, 1987, as amended at 59 FR 61417, Nov. 30, 1994; 67 FR 67078, Nov. 1, 2002]