Oxide inclusions are present in any killed steel grades and originate mainly from de-oxidation treatment or from re-oxidation with the slag or atmosphere. These inclusions are often detrimental in terms of productivity and product quality. The aim of this research is to evaluate: The effect of the de-oxidation practice, the ability of different slags to remove the non-metallic inclusion from the liquid steel on the inclusions properties (number, size and composition) and the final steel cleanliness. The benefits of these improved practices and slag compositions will be assessed on castability (SEN clogging) and final steel cleanliness.