the invention provides a method and formulation for cleaning a soiled substrate , the method comprising the treatment of the moistened substrate with a formulation comprising a multiplicity of polymeric particles , wherein the polymeric particles comprise at least one antimicrobial agent . preferably , the substrate is wetted so as to achieve a substrate to water ratio of between 1 : 0 . 1 to 1 : 5 w / w . optionally , the formulation additionally comprises at least one additional cleaning agent , and in this embodiment , it is preferred that the polymeric particles are mixed with the at least one additional cleaning agent . preferably , the additional cleaning material comprises a surfactant , which most preferably has detergent properties . most preferably , the substrate comprises a textile fiber . typically , the polymeric particles comprise particles of polyester or nylon , most preferably in the form of beads . the results obtained are very line with those observed when carrying out conventional aqueous cleaning processes and the method provides the significant advantage that the use of antimicrobial agents in or on the polymer bead greatly improves the overall hygiene in the washing machine by preventing mold and bacterial growth on the polymer particle surfaces , particularly at low temperatures .