Surface quality and metallurgical characteristics of extrusion ingot have a significant impact on the extrudability of the billet. Both the type of casting mould and mould maintenance significantly influences billet surface quality. ALBA, like the majority of extrusion ingot producers, uses moulds with graphite technology, where a mix of oil and gas is injected through a graphite ring into the mould to improve billet surface quality. ALBA has a policy of continual improvement in the areas of safety, product quality and productivity to enhance customer satisfaction. During 2008, an extensive campaign was conducted in ALBA’s casthouse to select the optimum type of casting rings for Airslip™ moulds supplied by Wagstaff Inc. The graphite casting rings evaluated must be suitable for the casting conditions and environment within the casthouse at ALBA. This paper details the methodology and the criteria set for the selection of the optimum graphite casting ring type as well as the results achieved. The results of the work showed a preference for L type casting rings, which enhance the quality of the extrusion ingots and extend the service life of the graphite ring.