It is very easy to tear the thin brass shield under the spring. Therefore it is possibly better to remove the cork seal, which is available as a spare and send the cap with spring and shield intact to the platers. Nothing will be then damaged. Beware of platers that polish too much, (don't ask me how I know), and fit a new seal afterwards with "Wellseal" or similar. I'm desperately chasing a cap with central OIL in larger text and "ESSOLUBE RACER", ", "PATENT CASTROL XXL", "AEROSHELL", "MOBILOIL D" and one other brand, I think, around the periphery. I have a genuine summer grades (U.S.A. Shadow) Vincent cap to swap, or a brand new T27L cap.