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A number of years ago we worked on a rent-a-solvent for a chemical company. A solvent is a chemical that is used to remove grease, for example, from machine parts. Companies ordinarily buy the cheapest degreasing solvent available, even if it comes from halfway around the globe. After its use, the waste solvent is either evaporated or entered into a waste treatment flow, to be handled a sewage treatment plant. The idea behind rent-a-solvent was to provide a degreasing service using high-quality solvents available to customers without selling the solvent itself; the provider would recapture the emissions and separate the solvent from the grease so that it would be available for continuous reuse. Under these circumstances, the company had incentive to use high-quality solvents (how else to retain customers?) and to reuse it, with the important side effect of keeping toxic materials out of waste flows.

Excerpted from Page 112 of ‘Cradle to Cradle’ by Michal Braungart and William McDonough