A set of processing oils, widely varying with respect to viscosity and chemical composition, was evaluated in different EPDM peroxide cure applications, such as black and non-black window gaskets and radiator hose compound formulations. Significant linear correlations between oil characteristics and material properties were obtained, thus allowing for the optimisation of the oil quality with respect to price and performance. It was found that equal or even better price/performance ratios can be obtained by replacing a standard paraffinic oil with a technical white oil, in spite of the higher cost of the latter. A lower amount of peroxide curatives is required for obtaining a similar vulcanisate performance. The concept was tested and proven to be successful on an industrial scale.