From the FCS Book of Little-Known Facts (pirate earplugs)

Pirate ships, well, the good ones, often had no less than 5 canons on board. Canons are loud in an open field, let alone in the belly of a large wooden ship. So, to avoid damage to the ears, pirates would often hang balls of wax from their earrings. Not only were these used as accessories, but the wax would also be plugged into their ears when canons were going off

There is never a time
to stop learning new things