[Bruce Lancaster]

I kinda think traditional aviation Permatex, sweet-smelling goo in a can with a brush in the lid. My can of it is about a million years old and has half the shell of a broken deuce ammeter stuck to it...
This stuff seals well and i think will disintegrate with a blast of carb cleaner so you can get the thing out in some future disaster.
Cleaning that surface...spray carb cleaner, then spray brake cleaner becasue it leaves no oily residue to interfere with sealing goo.