To assure the reliability and efficiency of the method we conducted a recovery experiment. For this purpose, we spiked 8 soil samples in a way that each contained 20 particles between 1-5 mm. These were 5 black foils (PE), 5 black fragments (PP), 5 white/green platelets (PE) and 5 fibres (PA). We processed the samples according to the method described above, and inspected them twice. Recovery success was 93%, while samples with high organic content in particular impaired the recovery of fibres.