<PAGE>
 
                                    GUARANTY


CoreStates


     This Guaranty is made and entered into by the undersigned, and by each of
them if more than one (the "Grantor"), for the benefit of CoreStates Bank,
N.A./1/, a national banking association (the "Bank").

     1.   Obligor.  The "Obligor" means the following person or entity, and if
more than one, any or all of the following persons or entities:

                 The JPM Company, a Pennsylvania corporation

     2.   Obligations.  The "Obligations" means all existing and hereafter
incurred or arising indebtedness, obligations and liabilities of the Obligor to
the Bank, whether absolute or contingent, direct or indirect and out of whatever
transactions arising, and includes without limitation, all matured and unmatured
indebtedness, obligations and liabilities of the Obligor under or in connection
with existing and future loans and advances evidenced by promissory notes or
otherwise, letter of credit, acceptances, all other extensions of credit,
repurchase agreements, security agreements, mortgages, overdrafts, foreign
exchange contracts and all other contracts for payments or performance,
indemnities, and all indebtedness, obligations and liabilities under any
guaranty or surety agreement, or as co-maker or co-obligor with any person for
any of the foregoing, including without limitation all interest, expenses, costs
(including collection costs) and fees (including reasonable attorney's fees and
prepayment fees) incurred, arising or accruing (whether prior or subsequent to
the filing of any bankruptcy petition by or against any Obligor) under or in
connection with any of the foregoing. If the term "Obligor" includes more than
one person or entity, the Obligations shall include all Obligations of any one
or more of such persons or entities, whether such Obligations are individual,
joint, several or joint and several.

     3.  Unconditional Guaranty.  In consideration of any existing Obligations
and any Obligations which may hereafter arise or be incurred, each Guarantor,
intending to be legally bound, absolutely and unconditionally (and jointly and
severally if more than one) guaranties to Bank the payment, performance and
satisfaction when due (whether by stated maturity, demand, acceleration or
otherwise) of all Obligations. The obligations of the Guarantor hereunder shall
continue in full force and effect irrespective of the validity, legality or
enforceability of any agreements, notes or documents pursuant to which any of
the Obligations arise, or the existence, value or condition of any collateral
for any of the Obligations, or of any other guaranty of the Obligations, or any
other circumstances which might otherwise constitute a legal or equitable
discharge of a surety or guarantor.

     4.  Cost of Enforcement.  Each Guarantor agrees (jointly and severally if
more than one) to pay Bank all costs and expenses (including reasonable
attorneys' fees) at any time incurred by Bank in the enforcement of this
Guaranty against any Guarantor.

     5.  Payment by Guarantor.  Payment by each Guarantor is due upon demand by
Bank and is payable in immediately available funds in lawful money of the United
States of America.

     6.  Continuing Guaranty.  This Guaranty shall continue in full force and
effect with respect to each Guarantor and may not be revoked until all existing
Obligations and all Obligations hereafter incurred or arising have been paid,
performed and satisfied in full. Notwithstanding the foregoing, any Guarantor
may, by written notice to Bank, terminate its

------------------------
/1/ CoreStates Bank, N.A. also conducts business as Philadelphia National Bank,
as CoreStates First Pennsylvania Bank and as CoreStates Hamilton Bank.
<PAGE>
 
liability hereunder with respect to Obligations which are not Pre-Termination
Obligations as hereinafter defined.  Such notice shall be ineffective unless
sent via certified mail to:
 
                             CoreStates Bank, N.A.
                              30 North Third Street
                                  P. O. Box 1071
                              Harrisburg, PA  17108
                            Attn:  David Diffenderffer
                                        
The burden of establishing (i) that Bank has received any termination notice
hereunder and (ii) the day on which such notice was received shall be on
Guarantor.  In the event that Bank receives an effective termination notice from
Guarantor in accordance with the provisions of this paragraph, such termination
shall not affect Guarantor's liability (a) for Obligations incurred or arising
on or prior to the tenth day following receipt by Bank of such termination
notice, or any earlier day, on which Bank determines in good faith that the
appropriate Bank officers have actual knowledge of Bank's receipt of such notice
(the "Termination Effective Date"), (b) for Obligations which are renewals,
modifications, amendments, extensions, substitutions, replacements or rollovers
of, or which consist of accrued interest on.  Obligations incurred or arising on
or prior to the Termination Effective Date, or (c) for Obligations incurred or
arising pursuant to a commitment existing on the Termination Effective Date
under which Bank was obligated to extend credit or make payments to Obligor or
for Obligor's account,/2/ all Obligations referred to in this sentence being
hereinafter collectively called "Pre-Termination Obligations".  It is understood
that for purposes of this Guaranty and regardless of any conflicting agreement
between Bank and any Obligor, all payments on and other reductions of the
Obligations subsequent to the Termination Effective Date (other than payments
made by Guarantor in respect of the Guaranty itself) shall, unless Bank elects
otherwise in writing, be applied first to Obligations other than Pre-Termination
Obligations, and then to Pre-Termination Obligations.  It is further understood
that the provisions of the preceding sentence shall be applicable regardless of
the amount of any Obligations incurred or arising subsequent to the Termination
Effective Date.

     7.  Waivers and Consents by Guarantor. Each Guarantor unconditionally
consents to, and waives as a defense to liability hereunder, each of the
following: (a) any waiver, inaction, delay or lack of diligence by Bank in
enforcing its rights against any Obligor or in any property, or the
unenforceability of any such rights, including any failure to perfect, protect
or preserve any lien or security interest which may be intended directly or
indirectly to secure any of the Obligations, and the absence of notice thereof
to any Guarantor, (b) the absence of any notice of the incurrence or existence
of any Obligation, (c) any action, and the absence of notice thereof to any
Guarantor, taken by Bank or any Obligor with respect to any of the Obligations,
including any release, subordination or substitution of any collateral or
release, termination, compromise, modification or amendment of any instrument
executed by or applicable to any Obligor or of any claim, right or remedy
against any Obligor or any property, (d) any impairment of Guarantor's right to
reimbursement by way of subrogation, indemnification or contribution, (e) any
other action taken or omitted by Bank in good faith with respect to the
Obligations, (f) the absence or inadequacy of any formalities of every kind in
connection with enforcement of the Obligations, including presentment, demand,
notice and protest, and (g) the waiver of any rights of Bank under or any action
taken or omitted by Bank with respect to any other guaranty of the Obligations.

     8.  Other Agreements By Guarantor.  Each Guarantor agrees that there shall
be no requirement that Bank document its acceptance of this Guaranty, evidence
its reliance thereon, or that Bank take any action against any person or any
property prior to taking action

-----------------------
/2/ Including without limitation all obligations arising out of that $20,000,000
line of credit extended by Bank to obligor pursuant to that Loan Commitment
dated May 28, 1997.
<PAGE>
 
against any Guarantor.  Each Guarantor further agrees that Bank's rights
and remedies hereunder shall not be impaired or subject to any stay, suspension
or other delay as a result of Obligor's insolvency or as a result of any
proceeding applicable to Obligor or Obligor's property under any bankruptcy or
insolvency law.  Each Guarantor also agrees that payments and other reductions
on the Obligations may be applied to such of the Obligations and in such order
as Bank may elect.

     9.  Subrogation and Similar Rights.  No Guarantor will exercise any rights
with respect to Bank or any Obligor related to or acquired in connection with or
as a result of its making of this Guaranty which it may acquire by way of
subrogation, indemnification or contribution, by reason of payment made by it
hereunder or otherwise, until after the date on which all of the Obligations
shall have been satisfied in full. Until such time, any such rights against the
Obligor shall be fully subordinate in lien and payment to any claim in
connection with the Obligations which Bank now or hereafter has against the
Obligor. If any amount shall be paid to any Guarantor on account of such
subrogation, indemnification or contribution at any time when all of the
Obligations and all other expenses guaranteed pursuant hereto shall not have
been paid in full, such amount shall be held in trust for the benefit of Bank,
shall be segregated from the other funds of Guarantor and shall forthwith be
paid over to Bank to be applied in whole or in part by Bank against the
Obligations, whether matured or unmatured, in such order as the Bank shall
determine in its sole discretion. If Guarantor shall make payment to the Bank of
all or any portion of the Obligations and all of the Obligations shall be paid
in full. Guarantor's right of subrogation shall be without recourse to and
without any implied warranties by Bank and shall remain fully subject and
subordinate to Bank's right to collect any other amounts which may thereafter
become due to the Bank by the Obligor in connection with the Obligations.

account of any Obligations and Bank repays all or part of said amount by reason
of (a) any judgment, decree or order of any court or administrative body having
jurisdiction over the Bank or any of its property, or (b) any settlement or
compromise in good faith with any such claimant (including Obligor), then and in
such event each Guarantor agrees that any such judgment, decree, order,
settlement or compromise shall be binding upon the Guarantor, notwithstanding
any termination hereof or the cancellation of any note or other instrument
evidencing any Obligation, and each Guarantor shall remain liable to the Bank
hereunder for the amount so repaid or recovered to the same extent as if such
amount had never originally been received by Bank.

     11.  Security Interest.  Each Guarantor hereby assigns to the Bank and
grants to the bank a security interest in any balance or assets in any deposit
or other account of such Guarantor in or with the Bank whenever and so long as
any of the Obligations shall be outstanding and unpaid and agrees that the
security interest hereby granted shall be independent of the right of setoff.

     12.  Financial Information on Guarantor.  Each Guarantor hereby agrees to
provide the Bank with such information on the business affairs and finance
condition of such Guarantor as the Bank from time to time may reasonably request
and to notify the Bank of any change in the address of such Guarantor.  In the
event that such Guarantor fails to comply with a request for information as
herein agreed, within ten (10) days after receipt of the request, such Guarantor
upon demand by the Bank agrees to purchase from the Bank without representation,
warranty or recourse the Obligations and to pay therefor the unpaid principal
amount of all such Obligations, including interest thereof to the date of
purchase.

     13.  Effect of Other Agreement.  The provisions of this Guaranty are
cumulative and concurrent with Bank's rights and remedies against Guarantor
under any existing or future agreement pertaining or evidencing any of the
Obligations. No such additional agreement shall be deemed a modification or
waiver hereof unless expressly so agreed by Bank in writing. If Bank holds any
other guaranty or surety agreement applicable to any of the Obligations, the
<PAGE>
 
liability of each Guarantor hereunder shall be joint and several with each party
obligated on such other guaranty or surety agreement, unless otherwise agreed by
Bank in writing.

     14.  Confession of Judgment; Waiver of Attorney  Each Guarantor irrevocably
authorized and empowers any attorney or any clerk of court of record, upon the
occurrence of a default or an Event of Default under or in connection with any
of the Obligations, or at any time thereafter, to appear for and confess
judgment against such Guarantor for the full amount of such Guarantor's
liability under paragraph 3 hereof, with or without declarations, with costs of
suit and release of errors, without stay of execution and without an amount not
to exceed the greater of five percent (5%) of the principal amount of such
judgment or $5,000 added for collection fees.  If a copy of this Guaranty,
verified by affidavit by or on behalf of Bank, shall have been filed in such
action, it shall not be necessary to file the original of this Guaranty.  The
authority granted hereby shall not be exhausted by the initial exercise thereof
and may be exercised by Bank from time to time.  There shall be excluded from
the lien of any judgment obtained solely pursuant to this paragraph all improved
real estate in any area identified by the Federal Emergency Management Agency as
having special flood hazards if the community in which such area is located is
participating in the National Flood Insurance Program.  Any such exclusion shall
not affect any lien upon property not so excluded.

     15.  Guarantor's Address.  Guarantor warrants and represents that the
address set forth below is Guarantor's correct mailing address and agrees
immediately to notify Bank in the event of any change therein.

     16.  Miscellaneous.  (a) No amendment of any provision of this Guaranty
shall be effective unless it is in writing and signed by each Guarantor and
Bank, and no waiver of any provisions of this Guaranty, and no waiver or consent
to any departure by the Guarantor therefrom, shall be effective unless it is in
writing and signed by Bank, and then such waiver or consent shall be effective
only in the specific instance and for the specific purpose for which given. (b)
Any provision of this Guaranty which is prohibited or unenforceable in any
jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining portions hereof or affecting
the validity or enforceability of such provisions in any other jurisdiction. (c)
The obligations of such Guarantor hereunder shall not be subject to any
counterclaim, setoff, deduction or defense based upon any related or unrelated
claim which such Guarantor may now or hereafter have against Bank or any
Obligor, except payment of the Obligations, and shall not be affected by any
change in Obligor's legal status or ownership or by any change in corporate,
partnership or other organizational structure applicable to Obligor. (d) This
Guaranty shall (i) be binding on each Guarantor and its personal
representatives, estate, heirs, successors and assigns, and (ii) inure, together
with all rights and remedies of Bank hereunder, to the benefit of the Bank and
its successors, transferees and assigns. Notwithstanding the foregoing clause
(i) none of the rights or obligations of any Guarantor hereunder may be assigned
or otherwise transferred without the prior written consent of the Bank. (e) This
Guaranty shall be governed by and construed in accordance with the internal
laws, and not the law of conflicts, of the Commonwealth of Pennsylvania.

     17.  CONSENT TO JURISDICTION AND VENUE.  IN ANY LEGAL PROCEEDING INVOLVING,
DIRECTLY OR INDIRECTLY, ANY MATTER ARISING OUT OF OR RELATED TO THIS GUARANTY OR
THE RELATIONSHIP EVIDENCED HEREBY, EACH UNDERSIGNED PARTY HEREBY IRREVOCABLY
SUBMITS TO THE NONEXCLUSIVE JURISDICTION OF ANY STATE OR FEDERAL COURT LOCATED
IN ANY COUNTY IN THE COMMONWEALTH OF PENNSYLVANIA WHERE BANK MAINTAINS AN OFFICE
AND AGREES NOT TO RAISE ANY OBJECTION TO SUCH JURISDICTION OR TO THE LAYING OR
MAINTAINING OF THE VENUE OF ANY SUCH PROCEEDING IN SUCH COUNTY. EACH UNDERSIGNED
PARTY AGREES THAT SERVICE OF PROCESS IN ANY SUCH PROCEEDING MAY BE DULY EFFECTED
UPON IT BY MAILING A COPY THEREOF, BY REGISTERED MAIL, POSTAGE PREPAID, TO EACH
UNDERSIGNED PARTY.
<PAGE>
 
     18.  WAIVER OF JURY TRIAL.  EACH UNDERSIGNED PARTY WAIVES, AND BANK BY ITS
ACCEPTANCE HEREOF THEREBY WAIVES, TRIAL BY JURY IN ANY LEGAL PROCEEDING
INVOLVING, DIRECTLY OR INDIRECTLY, ANY MATTER (WHETHER SOUNDING IN TORT,
CONTRACT OR OTHERWISE) IN ANY WAY ARISING OUT OF OR RELATED TO THIS GUARANTY OR
THE RELATIONSHIP EVIDENCED HEREBY.  THIS PROVISION IS A MATERIAL INDUCEMENT FOR
BANK TO ENTER INTO, ACCEPT OR RELY UPON THIS GUARANTY.



     IN WITNESS WHEREOF, each Guarantor has executed this Guaranty as of the
____ day of May, 1997.



                       THE JPM COMPANY OF DELAWARE, INC.
                  NAME OF CORPORATION OR PARTNERSHIP GUARANTOR

                      Route 15 North, Lewisburg, PA  17837
                                    ADDRESS


By: /s/ John H. Mathias
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