EXHIBIT 4.1

                     SECOND AMENDMENT TO RIGHTS AGREEMENT
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     SECOND AMENDMENT dated as of November 20, 1997 (the "Second Amendment") to
the Rights Agreement dated as of November 9, 1988, as amended (the "Rights
Agreement"), between Safety-Kleen Corp., a Wisconsin corporation (the
"Company"), and The First National Bank of Chicago, as Rights Agent (the "Rights
Agent").

     Pursuant to Section 27 of the Rights Agreement, the Company and the Rights
Agent may from time to time amend the Rights Agreement in accordance with
Section 27 thereof. All acts and things necessary to make this Second Amendment
valid and enforceable have been performed and done, including, as required by
Section 27(b) of the Rights Agreement, the delivery by the Company to the Rights
Agent of certified resolutions of the Board of Directors of the Company. Unless
the context otherwise requires, terms not defined herein have the same meanings
as in the Rights Agreement.

     In consideration of the foregoing and the mutual agreements herein, the
Company and the Rights Agent agree as follows:

     1. Section 1(a) of the Rights Agreement is hereby amended by deleting the
first sentence of that section and substituting the following therefor:

     "(a) "Acquiring Person" shall mean any Person who or which, together
     with all Affiliates and Associates of such Person, shall be the
     Beneficial Owner of 20% or more of the aggregate number of Common
     Shares of the Company then issued and outstanding, but shall not
     include (i) the Company, (ii) any Subsidiary, (iii) any employee
     benefit plan of the Company or any Subsidiary, (iv) any entity holding
     Common Shares for or pursuant to the terms of any such plan, or (v) SK
     Parent Corp., a Delaware corporation ("Parent"), SK Acquisition Corp.,
     a Wisconsin Corp. ("Purchaser"), or any Affiliate or Associate of
     Parent or Purchaser; provided, however, that Parent, Purchaser and the
     Affiliates and Associates of Parent and Purchaser will not be excepted
     from this definition of "Acquiring Person" in the event that any of
     Parent, Purchaser or any Affiliate or Associate of Parent or Purchaser
     becomes the Beneficial Owner of 20% or more of the aggregate number of
     Common Shares of the Company then issued and outstanding other than
     pursuant to the terms of the Agreement and Plan of

 
     Merger, dated as of November 20, 1997 (the "Merger Agreement"), between the
     Company, Parent and Purchaser.

     2.   Section 3(a) of the Rights Agreement is hereby amended by adding as
the final sentence thereto the following:

     "Notwithstanding anything in this Agreement to the contrary, a Distribution
     Date shall not be deemed to have occurred solely as a result of (i) the
     approval, execution or delivery of the Merger Agreement, or (ii) the
     commencement or consummation of the transactions contemplated by the Merger
     Agreement."

     3.   Section 11(a)(ii) of the Rights Agreement is hereby amended by adding
as the final sentence thereto the following:

     "Notwithstanding anything in this Agreement to the contrary, an event
     described in this subparagraph (ii) of Section 11(a) shall not be deemed to
     have occurred solely as a result of (i) the approval, execution or delivery
     of the Merger Agreement, or (ii) the commencement or consummation of the
     transactions contemplated by the Merger Agreement."

     4.   Section 13(a) of the Rights Agreement is hereby amended by adding as
the final sentence thereto the following:

     "Notwithstanding anything in this Agreement to the contrary, an event
     described in any of clauses (i), (ii) or (iii) of this Section 13(a) shall
     not be deemed to have occurred solely as a result of (i) the approval,
     execution or delivery of the Merger Agreement, or (ii) the commencement or
     consummation of the transactions contemplated by the Merger Agreement."

     5.   This Second Amendment shall be governed by and construed in accordance
with the laws of the State of Wisconsin applicable to contracts made and
performed entirely within such state.

     6.   In all respects not inconsistent with this Second Amendment, the
Rights Agreement is hereby ratified, approved and confirmed.  In executing and
delivering this Second

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Amendment, the Rights Agent shall be entitled to all the privileges and
immunities afforded to the Rights Agent under the Rights Agreement.

     7.   If any term, provision, covenant or restriction of the Second
Amendment is held by a court of competent jurisdiction or other authority to be
invalid, void or unenforceable, the other terms, provisions, covenants and
restrictions of this Second Amendment, and of the Rights Agreement, shall remain
in full force and effect and shall in no way be affected, impaired or
invalidated.

     8.   This Second Amendment may be executed in any number of counterparts,
each of which shall be an original, but all of which shall together constitute
one and the same instrument.

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     IN WITNESS WHEREOF, the parties hereto have caused this Second Amendment to
be duly executed and attested, all as of the date first above written.

                              SAFETY-KLEEN CORP.

                              By: /S/ DONALD W. BRINCKMAN
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                              THE FIRST NATIONAL BANK OF CHICAGO

                              By: /S/ LARRY WOODS
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