On interior hidden metal, I then hit it with 3M Cavity Wax[/url
In all cases, follow the instructions for use.
Not familar with this 3m product but it's ofter an issue with wax base products,they trap moisture and cause rust!! In texas I would imagine it's only a very slight issue but anywhere they use salt on the roads this can make things much worse!!!
I'd advise an oil treatment,there's many on the market and most work well but need to be reapplied on an annual/semi annual basis!
Chain oils,the type you spray on bike chains and the like works real well,but it doesnt last so it needs to be reapplied!
Rustcheck and Krown both make spray cans of their products,how the availability is in the USA I dont know but either work real well at stopping and preventing rust. There are others on the market as well that work good but what you want is an oil that is thin,sticks and has capillary action(creeps around)...
Products like wax and tar base stuff tends to trap mopisture and cause problems you dont see until it's too late!
Again it depends on where you live! Did you know that rust almost doesnt happen below freezing? It's the salts and other products that lower the melting point of water that are the real problem. If it's too cold to use salts.etc. you have very little rusting issues,there a reason they call it the rust belt!!! Just warm enough to allow the use of salts and therefore promote rust!
Ya in another life I managed a rust proofing company!