Hi all, I have a lovely Montblanc 134 long captop but the caesin star just won't stay on. Every time the barrel is screwed into the pen, the star pops out in response. As a result of it being this loose, it's prone to leaking. Ordinarily, I'll paint the sides of the star with some shellec or rosin, and leave it dry. But since it's such an old pen, and since I've never dealt with caesin, I'm not sure if using shellac would dissolve the star. Can the wise sages here weigh in on what are the proper steps to take? Thank you!!