The present disclosure relates generally to a method comprising: providing an aqueous medium comprising at least one of microplastics and nanoplastics; combining an agglomerizer and the aqueous medium, wherein the agglomerizer has at least one C8-C32 hydrocarbon group; mixing the agglomerizer and aqueous medium to form at least one agglomerate of the at least one microplastics and nanoplastics having a d50 particle size in the range of 1 to 100 mm; and separating the at least one agglomerate from the aqueous medium. The present disclosure also generally relates to a method comprising: providing an aqueous medium comprising at least one of microplastics and macroplastics; adding a solubilizer to the aqueous medium, wherein the solubilizer has at least one C6-C32 hydrocarbon group; and mixing the solubilizer and the aqueous medium to form a suspension of plastic particles, wherein the plastic particles in the suspension of plastic particles have a d50 particle size in the range of 10 nm to 10 μm.