I own a decades-old Silva Ranger compass. It has gradually developed a serious bubble in the liquid. I have searched the threads and seen the "warming recommendations." Have tried that and the bubble was reduced about 25%. So, now I put it to the forum:

1 - any more ideas on how to "home fix" the bubble in the compass problem?

2 - if not, to whom should I appeal for factory help on a VERY old Ranger? (faint hope, I know!)