There is disclosed a method and apparatus for clearing waste water pipes and/or grease traps clogged with grease, with the method comprising the steps of: providing a dry agent comprising bacteria and enzymes; mixing dry agent comprising bacteria and enzymes with an amount of water sufficient to cause in-situ production of an aqueous mixture; maintaining the aqueous mixture in an activator vessel structure to activate the aqueous mixture for a time sufficient to form an aqueous solvent for cleaning or clearing fatty residues and/or grease; contacting the waste water pipes and/or grease traps containing fatty residues and/or grease with the aqueous solvent to dissolve the grease and/or fatty residues; and thus cleaning the waste water pipes and/or grease traps by biodigesting fatty residues and/or grease deposited in the waste water pipes and/or grease traps.