Living in Washington, condensation corrosion in a vehicle is a major concern.
Over several years I've tried a number of corrosion inhibitors for firearms and some of my more costly tools/machines. Nothing is perfect, nothing works under any and all circumstances, but... this is what I've found with these products.
- Boeshield. I worked for Boeing, so this was "free"... works well but leaves a waxy film. Great for non-working surface stuff.
- Starrett M-1. This works well on bare steel tools machines and equipment, and dries completely.
- Eezox. This has been around the gun world for quite some time and usually finishes in the top 2 or three products in testing. 6BR test. I have never tried the Corrosion X product as described in this test.
- Tipton Rust Inhibitor Chips. I didn't have much faith in these when I bought them, so I tried them out first with low buck items. They work very well in a small storage box application. Die boxes, plastic gun boxes... toss a few in a gun box and you're good to go. Really... I'm still kinda surprised.
- Inhibitor VCI corrosion products. This is what I've been using mostly for the past 2 years... or rather a combination of Eezox and VCI firearm bags. For "car guns" and "shop guns" - I clean the gun, apply Eezox to all parts inside and out, wipe off excess, drop firearm in a VCI bag... and away we go.
So that's it. Some of these products are easier to find at your LGS than others, most can be ordered via the interweb.