Wrap a good bronze bore brush with unwrapped Chore Boy copper scouring pads. Chuck the rod up in your drill motor and stroke the bore while spinning. If it takes 30 seconds to clean the leading out something is wrong. Then follow with chlorinated brake cleaner to get all the plastic out, then brush as normal with solvent for the squeaky clean finish and oil to prevent rust. Total time to clean is less than 3 minutes.