Compass refill.
Years ago I bought an old Sestrel 4" compass that had a bubble in it & I was advised to put it in the deep-freezer for 2 hours before topping it up with alcohol & although I could not get all the air out , by the time it warmed up the bubble was gone. I do not know if it will work with your compass but maybe there is some-one out there that can offer a suggestion.
John N.W.W.