Our adapted KOH digestion technique can cope with a large fraction of the entire microplastics range, therefore being suitable for a range of studies. Earlier studies of bivalve tissues achieved recovery with single-digit μm filters, but might have underestimated microplastic concentrations. These studies either employed a combination of digestion and density separation, digested with acids or digested only small amounts of tissue. Interestingly, while Catarino et al(2017) achieved a digestion efficacy of 100% for bivalve tissues using a similar reagent (1 M of NaOH) over 0.8 μm filters, Cole et al(2014) obtained 90% zooplankton tissue removal over 50 μm filters. This suggests that digestion techniques may not universally applicable between different phyla. We achieved digestate filtration over 1.2 μm. Capturing smaller particles still comes with further challenges as confirmation of chemical composition through spectro-fingerprinting (Raman and FTIR approaches) is limited at these sizes.