I have a JG serial X Metal Juliet, with slight ageing signs to the bridge if you'd like to have a go with that palresult is very consistent and this was a very rough job I did tonight, so the pics aren't the best. There may still be faint yellowing on certain parts of the orbital that can only be verified in daylight.
PM me if you need my servicing. I can also restore X-metal grey frames back to original.