I have used a product called Super Lube for years on everything from guns to boats. It's a clear silicone based grease on a evaporating carrier. Penetration is good and it's supposed to be resistant to salt water. I can say that it protects my guns (spray on a piece of flannel and make a gun cloth) very well and I get much better protection from fingerprints. It's in a silver can and comes in aerosol and tube style. I believe you would be pleased with the way it would do what you need. I've never been disappointed.
Wake me up early,
Be good to my dogs,
and teach my children to pray.