More details needed, but I will put forth my standard "thing" on rust --assuming your smudges are actually rust.
You're near a body of salt water.
Salt water waves create splashes.
Splashes create tiny droplets of salt water.
The water in these droplets evaporates, leaving tiny bits of solid sea salt floating around in the air. These tiny bits of salt can be carried long distances inland by the breeze, where they can be deposited on things, creating rust. They get everywhere.
They even get on things that were touched by things they got on.
How it got through the laquered or plastic coating on your cases I can't say --abraded spots from jostling or feeding through a gun mechanism, from wiping them clean, whatever. But once rust starts it will lift up the coating and creep further. (Rust takes up a greater volume than the ferrous material it forms on.) This could be the cause of your smudge-like patches.
In general, rust will not form from corrosive materials deposited on dry ferrous materials until the humidity hovers around 50%. In general.
Your humidity in Panama CIty is right around 55% this afternoon --I just looked.
I used to live in New York City, [STRIKE]five[/STRIKE] four out of five Boroughs of which are on islands surrounded by salt water. It was virtually impossible to keep ferrous materials from rusting without taking great care in wiping, etc.
Iron fence posts, road signs, tools... everything got rusty. That's why most boating furniture (clevises, pulleys, oarlocks, whatever) was made of brass or bronze.
The war against rust was an ongoing, almost-unwinnable war, regardless of what you were trying to protect.
There. That's my "thing" on living near salt water.
Terry, 230RN
