Cellulosic based cores used in manufacture of towel and tissue products can be effectively stripped of residual product with little damage to the core using a roll stripping air knife with a longitudinal air passageway having both primary discharge passages and interconnected auxiliary orifices, the auxiliary orifices are directed laterally away from the primary discharge direction and connect with a longitudinal exterior channel configured such that air flows inwardly through the auxiliary orifices when pressurized air is supplied to longitudinal air passageway and the primary discharge passages are unobstructed but outwardly when the primary discharge passages are obstructed so that the pressure achievable when the primary discharge passages are obstructed is within safety limits.