"First would be a storage locker in the bilge of a salt water vessel."
Which exactly describes where I am sitting today, and sit 6 months of each year.
I keep my tools in the engine room of my boat, which is essentially the bilge, and have the locking storage area there required by the Bahamas for secure storage of guns imported into the Bahamas as well. Not to mention that the cabin is always at 100% humidity and that everything gets salty. So... take this for what it's worth:
VCI bags work better than any spray-on stuff. If you want to spray and then bag, you're really ahead of the game. I use VCI bags two ways, bearing in mind that I buy rolls of heat sealable tube and use a Walmart variety vacuum food bagger to as both a heat sealer to close the ends of the tubes to make sleeves and bags, and also to vacuum pack "sometimes".
Way #1: I take a length of VCI tube, use the vacuum bagger to heat-seal one end to make a sleeve, tuck steel goodies into it, and use a bit of duct-tape to close the end of the tube after I fold it over twice. This gives good access to things that use now and then. I leave a tab of duct tape folded back on itself to make it easy to pull the tape back for opening and reclosing them. This is where I keep screwdrivers, wrenches, and things like my Keltec SUB-2000 which sits in a locker up on the flybridge. No heat sealer? No worries: Just use duct tape.
Way #2: For things that are being put into long term dead-storage: I use the vacuum bagger to actually vacuum-bag what I want to keep. Examples are the spare tools in the grab-bag that sits in the inflatable Zodiac boat I tow behind, spare parts in the engine room, spare ammunition and magazines that I don't need immediate access to, etc. I've kept tools, spark plugs, etc., like this for 5 years in a bag that get's tossed literally into the bottom of my Zodiac boat where there's often 3 inches of salt water and the stuff is as good as new.
The VCI tube on rolls and the pre-made bags are so cheap that it's silly. For under a $100 you can set yourself up for life.
In less critical places, spray-away with whatever stuff you like. But if you want it to REALLY stay preserved, this is the way to go.
Pelican cases, etc.... Great physical protection, but when you close them you lock in whatever atmosphere you lock in. If that's wet-air, you're going to be unhappy when you open it up. And they are way too bulky to use in a confined space.
This is based on real-world experience living continuously aboard a boat for half of each year. At home my good stuff that I don't handle regularly is also VCI bagged and stuck into my safe. When I die I'm sure it'll be fun for my heirs to open the bags. I bet there's not gonna be a speck of rust on anything.
Willie
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