One of the flasks I use to prime my guns is a small flattened horn. Had it for years, found it at a flea market.
Still looks good, but the wooden plug has shrunk and it's started leaking. Primimg powder can leak out of the tiniest gap.
I need to reseal it somehow. I'm thinking maybe I can wick something thin into the seam around the base plug. The gap is barely visible, but it's enough to leak FFFFg.