Abstract: The present method for improving the quality of injection molded optical components consists of proper cleaning of the injection molding apparatus between uses. Injection parts that are not subjected to pressurized polymer are cleaned by passage through a series of isopropyl alcohol baths. At each stage clean brushes are used to remove any contaminating polymer. Those injection parts that are subjected to pressurized polymer are best passivated by a succession of thermal cycles in isopropyl alcohol. Thermal cycling removes a contaminant or charge that promotes pre-curing of polymer during the injection process.