The invention relates to a method of separating a first contaminant from a feed stream further comprising a condensation polymer. The invention further relates to a reactor system for carrying out the method, comprising at least one depolymerization vessel, configured for depolymerizing a condensation polymer into monomer, dimer, trimer and/or oligomer, which depolymerizing occurs in an alcoholic solvent, wherein said condensation polymer is provided as a feed stream further comprising a first contaminant, the reactor system comprising a separation stage, said separation stage comprising a separation vessel, downstream of the depolymerization vessel, configured for collecting a first contaminant, wherein said first contaminant is separated from the alcoholic solvent on the basis of a density separation so that the first contaminant is arranged on top of the alcoholic solvent.