The reduction of MnO in slag by blends of coke with high density polyethylene (HDPE) was investigated by the sessile drop method at 1 500°C in this study. The results show improved wettability and extents of reduction are realised with the use of an HDPE/coke blend in this system by comparison to reduction by pure coke, whereby increasing HDPE content resulted in further improvement in extent of reduction and increased wettability. The extensive devolatilisation from HDPE samples is the primary cause for these improvements, whereby the gasified HDPE created both CH4 and H2 reducing gases. Additionally, increased sample porosity allowed for improved wetting, and thus improved reduction capabilities. The dynamic contact angle between the carbon substrate and the slag varied, with HDPE samples ranging between 140°-60°, whilst the coke samples ranged between 160°-120°. The addition of HDPE allowed for the near complete reduction of MnO and partial reduction of SiO2 from the slag with distinct metallic regions of Mn-Si formed in the sample; regions containing pure Si were also found.