MUTUAL GENERAL RELEASE

                                                                    Exhibit 10.6


                             MUTUAL GENERAL RELEASE

      KNOW ALL MEN BY THESE PRESENTS: that, for good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, Republic Services,
Inc., a Delaware corporation, for itself and on behalf of each of its
subsidiaries and their respective employees, officers, directors, partners,
shareholders, attorneys, agents, employees, subsidiaries, affiliates, insurers,
representatives and assigns (collectively referred to herein as the "Republic
Releasing Parties"), does hereby fully and unconditionally remise, release,
acquit, satisfy and forever discharge GreenMan Technologies, Inc., a Delaware
corporation (the "Company"), and each of the employees, officers, directors,
partners, shareholders, attorneys, agents, employees, subsidiaries, affiliates,
insurers and representatives of the Company (collectively referred to herein as
the "GreenMan Released Parties"), of and from all, and all manner of, action and
actions, cause and causes of actions, suits, debts, dues, sums of money,
accounts, reckonings, bonds, bills, specialties, covenants, contracts,
controversies, agreements, promises, variances, trespasses, damages, judgments,
executions, injuries, claims and demands whatsoever, in law or in equity
(collectively, "Claims"), which the Republic Releasing Parties ever had, and now
have, or may have against the GreenMan Released Parties, whether known or
unknow