The present invention generally relates to a method for reducing polymer agglomeration or fouling, and its use in processes for the preparation of an acrylate, methacrylic acid, or a methacrylate. According to the present invention, the reagent comprises an alkyl phthalate, an alkaryl phthalate, an aryl phthalate, or a phthalic acid, and applying the reagent to processes for the preparation of an acrylate, methacrylic acid, or a methacrylate to prevent polymeric foulant precursors from agglomerating or to dissolve existing polymeric agglomerates or foulants so as to reduce polymer agglomeration or fouling in the process or storage equipment.