Air Bubble

I have used this kind of capacitor before (also dropped a few, and blown-up a
few.  A real mess, either way!).  Since you can see inside it, I suggest the
following:  Stand the cap up on one end and let the "bubble" migrate to the top
- if the oil covers the entire capacitor, mount it this way; if not, I don't
know what to tell you. Suggestions, anyone?
I have a similar cap by DEL but the case is ceramic.  It, however is stamped
"MOUNT THIS END UP", with an arrow pointing toward one end.  So, because I
always follow the rules, ( ;->) I did.
Hope this helps.