Document:

<PAGE>

                                                                  Exhibit 10(vi)
                                                                  --------------

                           STOCK REPURCHASE AGREEMENT
                           --------------------------

     THIS STOCK REPURCHASE AGREEMENT (this "Agreement") is made and entered into
this __ day of July, 2000, by and among Enviro-Clean of America, Inc., a Nevada
corporation (the "Company") and Thomas B. Haines ("Seller").

                                  WITNESSETH:

     WHEREAS,  Seller owns 500,000 shares of the common stock, $.001 par value,
of the Company ("Common Stock");

     WHEREAS, Seller desires to sell to the Company and the Company desires to
purchase from Seller 250,000 of Seller's 500,000 shares of the Common Stock
(said 250,000 shares hereinafter referred to as the "Shares"); and

     NOW, THEREFORE, in consideration of the mutual covenants herein contained
and other good and valuable consideration, the receipt and sufficiency of which
is hereby acknowledged, the parties, intending to be legally bound, hereby agree
as follows:

1.   Sale of Shares.
     ---------------

          Subject to the terms and conditions of this Agreement, and the
representations and warranties herein contained, Seller hereby agrees to sell
and the Company hereby agrees to purchase the Shares for the consideration
hereinafter described.

2.   Consideration.
     -------------

          The aggregate purchase price to be paid by the Company and received by
Seller for the Shares shall be five hundred thousand dollars ($500,000) (the
"Purchase Price") payable in accordance with Section 3(B) of this Agreement.

          (B) The parties shall execute a mutual general release in the form
attached hereto as Exhibit A (the "Release").

3.   Closing.
     -------

          (A)  Closing Date. The closing (the "Closing") shall take place at the
               ------------
offices of the Company, 1023 Morales, San Antonio, Texas 78207 upon execution of
this Agreement. The date of the Closing shall herein be referred to as the
"Closing Date."

          (B)  Payment of Purchase Price. The Purchase Price shall be payable at
               -------------------------
the Closing in the form of a wire transfer of immediately available funds or
cashier's check.
<PAGE>

          (C)  Seller's Closing Documents. Seller shall deliver, or cause to be
               --------------------------
delivered, to the Company at Closing:

               (i)    stock certificates for the Shares either duly endorsed to
          the Company by the registered holder thereof or accompanied by
          appropriate stock transfer powers duly executed;

               (ii)   the Release, duly executed by Seller; and

               (iii)  the spousal consent in the form attached hereto as Exhibit
          B, duly executed by Seller's wife.

          (D)  The Company's Closing Documents. The Company shall deliver, or
               -------------------------------
cause to be delivered, to Seller at the Closing:

               (i)    the Purchase Price; and

               (ii)   the Release, duly executed by the Company.

4.   Representations and Warranties of Seller.  Seller hereby represents
     ----------------------------------------
     and warrants to the Company as follows:

     (A)  Seller is the record owner of the Shares and: (i) the Shares are free
and clear of all security interests, pledges, liens, claims, options,
commitments, demands, charges, encumbrances, or covenants of any kind, (ii)
Seller has full legal power, right and authority, and all authorizations and
approvals to sell, transfer and deliver good and valid title to the Shares free
and clear of any encumbrances pursuant to the terms of this Agreement, (iii)
there are no existing impediments to the sale and transfer of the Shares except
as contemplated by this Agreement, and (iv) upon acquiring the Shares, the
Company shall be vested with good and marketable title to the Shares.

     (B)  In formulating Seller's decision to sell the Shares to the Company,
Seller has had the opportunity to ask questions and receive answers from the
Company concerning the Company and its business and prospects, and Seller has
been permitted to have access to all information which Seller has requested in
order to evaluate the merits and risks of the sale of the Shares by Seller
hereunder.  Seller has been represented by independent legal counsel with
respect to the sale of the Shares and has received such financial advice as
Seller deems necessary from financial advisors of Seller's choosing.  In
addition, Seller understands that the Company has recently issued its stock for
a price higher than the price it is paying to Seller for the Shares, that the
Company may repurchase shares at a price higher than $2.00 per share, and that
the Company may effect a sale of the Company or substantially all of its assets.

     (C)  No representations or warranty by Seller herein or in any writing
furnished or to be furnished pursuant hereto contains or will contain any untrue
statement of a material fact, or omit or will omit to state any material fact
necessary to make the statements therein contained true, complete and not
misleading.
<PAGE>

5.   Representation, Warranties and Covenants of the Company.  The Company
     -------------------------------------------------------
     represents, warrants and covenants as follows:

     (A)  Organization. The Company is a corporation duly organized, validly
          ------------
existing and in good standing under the laws of the State of Nevada, and the
Company has the power and authority to carry on its business as presently
conducted, to execute and deliver this Agreement, and to perform it obligations
hereunder.

     (B)  Authority. The execution and delivery of this Agreement and the
          ---------
effectuation of the transactions contemplated hereby have been duly and
unanimously authorized by the Company's Board of Directors, and no other act or
proceeding on the part of the Company is necessary for the due and valid
authorization of the Agreement or the transactions contemplated hereby.

6.   Conditions Precedent to Obligations of Seller.  The obligations of
     ----------------------------------------------
     Seller hereunder are subject to the following conditions precedent:

     (A)  Authority. The execution and delivery of this Agreement and the
          ---------
effectuation of the transactions contemplated hereby have been duly authorized
by the Company's Board of Directors, and no other act or proceeding on the part
of the Company is necessary for the due and valid authorization of the Agreement
or the transactions contemplated hereby.

     (B)  Performance. Each covenant and agreement of the Company set forth in
          -----------
this Agreement to be performed on or before the Closing Date shall have been
duly performed in all material respects.

     (C)  Representations and Warranties True. The representations and
          -----------------------------------
warranties of the Company contained in this Agreement shall have been true in
all material respects.

     (D)  No Violation of Statutes, Orders, etc. There shall not be in effect
          -------------------------------------
any statute, rule, or regulation which makes it illegal for Seller to consummate
the transactions contemplated hereby, or any order, decree, or judgment
enjoining Seller from consummating the transactions contemplated hereby.

7.   Conditions Precedent to Obligations of the Company.  The obligations
     --------------------------------------------------
     of the Company hereunder are subject to the following conditions precedent:

     (A)  Performance. Each covenant and agreement of Seller set forth in this
          -----------
Agreement to be performed on or before the Closing Date shall have been duly
performed in all material respects.

     (B)  Representations and Warranties True. The representations and
          -----------------------------------
warranties of Seller contained in the Agreement shall have been true in all
material respects.

     (C)  No Violation of Statutes, Orders, etc. There shall not be in effect
          -------------------------------------
any statute, rule, or regulation which makes it illegal for the Company to
consummate the transactions
<PAGE>

contemplated hereby, or any order, decree, or judgment enjoining the Company
from consummating the transactions contemplated hereby.

8.   Miscellaneous.
     -------------

     (A)  Brokerage. Seller and the Company each hereby represent and warrant to
          ---------
the other that neither has incurred any brokerage commissions in connection with
the sale of the Shares.

     (B)  Disclaimer. Seller and the Company each hereby waive any right or
          ----------
cause of action that any of them may now or in the future have against the other
or their respective affiliates, successors, assigns, transferees, directors,
officers, agents, or employees as a result of the sale and purchase of the
Shares hereunder; provided, however, that this waiver shall not extend to any
liability of a party hereto arising from the breach by said party of its
warranties, representations, covenants, and agreements contained in this
Agreement.

     (C)  Further Assurances. The parties will use reasonable efforts to
          ------------------
implement the provisions of this Agreement, and for such purpose a party, at the
request of the other party, at or after the Closing, will, without further
consideration, promptly execute and deliver, or cause to be executed and
delivered, such consents and other instruments in addition to those required by
this Agreement, in form and substance satisfactory to the other party, as is
reasonably necessary to implement any provision of this Agreement.

     (D)  Entire Agreement. This Agreement constitutes the complete and
          ----------------
exclusive statement of the agreement between the Company and Seller with respect
to the subject matter herein set forth, and supersedes all prior
representations, warranties, discussions, and agreements by and between the
parties.

     (E)  Amendments. This Agreement may not be amended, altered, or terminated,
          ----------
except in writing.

     (F)  Inurement. This Agreement shall be binding upon the parties hereto and
          ---------
their respective heirs, executors, administrators, legal representatives,
successors, and assigns.

     (G)  Language. The language used in this Agreement shall be deemed to be
          --------
language chosen by the parties thereto to express their mutual intent, and no
rule of strict construction against any party shall apply to any term or
condition thereof.

     (H)  Assignment. This Agreement may be assigned in whole or in part by the
          ----------
Company without the consent of the Seller.

     (I)  Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
          -------------
ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS.

     (J)  Gender. Wherever herein that the singular number is used, the same
          ------
shall include the plural, and the masculine gender shall include the feminine
and neuter genders, and vice versa, as the context may require.
<PAGE>

     (K)  Counterparts. This Agreement may be executed in counterparts, each of
          ------------
which shall constitute an original but all of which taken together shall
constitute one agreement.

(SIGNATURE PAGE FOLLOWS)
<PAGE>

(STOCK REPURCHASE AGREEMENT

COUNTERPART SIGNATURE PAGE)

          IN WITNESS WHEREOF, the parties have executed this Agreement on and as
of the date first written above.

                                  ---------------------------------------------
                                  THOMAS B. HAINES

                                  ENVIRO-CLEAN OF AMERICA, INC.

                                  By:
                                     ------------------------------------------
                                     Richard Kandel, Chief Executive Officer<PAGE>

                                                                    EXHIBIT 10.1

          AMENDMENT NO. 1, dated as of June 15, 2000 (the "Amendment") to the
CREDIT AGREEMENT (the "Credit Agreement"), dated as of June 21, 1999, among
BLOCKBUSTER INC., a Delaware corporation (the "Borrower"), the Bank parties
thereto from time to time, CITIBANK, N.A., as the Administrative Agent, THE
BANK OF NEW YORK, as the Documentation Agent, THE BANK OF AMERICA NT&SA, as a
Syndication Agent and CHASE SECURITIES INC., as a Syndication Agent.

                                  WITNESSETH:

          WHEREAS, the parties have heretofore entered into the Credit Agreement
providing for, among other things, a 364-day revolving commitment due to mature
on June 19, 2000;

          WHEREAS, the Tranche C Loan Banks now desire to amend the Credit
Agreement to extend the maturity date of the 364-day revolving loan commitment

          NOW THEREFORE, the parties hereto agree as follows:

          SECTION 1.  Amendment.  Section 1.1 of the Credit Agreement is hereby
                      ---------
amended by replacing "June 19, 2000" in the definition of "Tranche C Loan
Commitment Termination Date" with "December 14, 2000".

          SECTION 2.  Effectiveness.  This Amendment will be effective upon the
                      -------------
execution of counterparts hereof by the Borrower and each of the Tranche C Loan
Banks.

          SECTION 3.  Representations and Warranties.  The Borrower hereby
                      ------------------------------
represents and warrants that as of the date hereof (i) the representations and
warranties contained in Article VI of the Credit Agreement (other than those
stated to be made as of a particular date) are true and correct in all material
respects on and as of the date hereof as though made on the date hereof, and
(ii) no Default or Event of Default shall exist or be continuing under the
Credit Agreement.

          SECTION 4.  Miscellaneous.  (a) Capitalized terms used herein and not
                      -------------
otherwise defined herein shall have the meanings ascribed to them in the Credit
Agreement.

          (b) Except as amended hereby, all of the terms of the Credit Agreement
shall remain and continue in full force and effect and are hereby confirmed in
all respects.

          (c) This Amendment shall be a Loan Document for the purposes of the
Credit Agreement.

<PAGE>

          (d) This Amendment may be signed in any number of counterparts, each
of which shall be an original, with the same effect as if the signatures thereto
were upon the same instrument.  Delivery of an executed counterpart of a
signature page of this Amendment by telecopier shall be effective as delivery of
a manually executed counterpart of the Amendment.

          (e) THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HERETO SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE
STATE OF NEW YORK.

                                      -2-

<PAGE>

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

                                    BLOCKBUSTER INC., as Borrower

                                    By:  /s/ RICHARD McDOWELL
                                       -----------------------------------------
                                       Name:     Richard McDowell
                                       Title:    Senior Vice President/Treasurer

                                    CITIBANK, N.A., as a Bank

                                    By:  /s/ ROBERT PARR
                                       -----------------------------------------
                                       Name:     Robert Parr
                                       Title:    M.D.

                                      -3-

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]