ArcelorMittal Atlantique has developed the DWI Ultra Low Aluminium grades to improve the rejection rates during the deep drawing of beverage cans. At the time of industrialization of this grade, an increase of slivers defects was recorded. The analysis of these slivers permitted to trace down their origin to the continuous casting powder. The compared analysis of slags during casting, respectively on standard DWI and ULA DWI, pointed out infiltration phenomena and inclusion pick-up. A high viscosity powder was formulated. An acceptable sliver rate was achieved with a strong decrease in downstream repaired coils.