Storage in a silicon impregnated gun sock/sleeve/whatever you want to call it is useful, too. I will often put a gun I just handled back into its sock and then literally rub the gun with the sock. Gun socks have two great uses. One is to protect the finish of your gun; the other is they are way more useful for long term storage than a typical gun rug because they take up less space whilst they continue to protect the firearms.

One has to remember that sweat, fingerprints, similar body "exudates" are more than just water; there are chemical elements, salts and such, that are not good for gun finishes.