I don't have a way to make plastic new, but I've had good results with WD40 for restoring surfaces with WD40. Some plastics get dusty and highly ablative on the surface with age and environment. Plastic LOVES WD40, if it is 'thirsty' Coat the plastic with WD40, and wait. It will soak in, sometimes it takes an overnight. Repeat this until the plastic no longer 'drinks' the WD40. You've done all you can do now with this method. I don't know that it restores the original strength of plastic, I doubt that, but it sure helps with the surfaces' appearance and wear resistence. Best, Jeff