A plastic cleaning method for cleaning a plastic article in an automatic dishwashing machine is provided, comprising: selecting an automatic dishwashing composition for cleaning plastic, wherein the automatic dishwashing composition, comprises: a builder; a phosphonate a nonionic surfactant; and a dispersant polymer comprising: (a) 60 to 98 wt % of structural units of formula I




wherein each R1 is independently selected from a hydrogen and a —CH3 group; and (b) 2 to 40 wt % of structural units of formula II





wherein each R2 is independently selected from an alkyl group with at least 4 carbon atoms and wherein each R3 is independently selected from a hydrogen and a methyl group.