I use RemOil for general cleaning. I have no expectations it will prevent rust for 1 year let alone longer. If I am going to be storing something for a long time, I will be using vapor bags with VCI tabs and not Hefty.
I read somewhere that Cosmoline had a similar chemical composition to preservatives used by Ancient Egyptians as part of the mummification process. The name has been around since the early 1800s though. Something doesn't last that long without being good at what it does. The most important thing when cleaning it out is to repeat "I love Cosmoline" as you scrub.
Thats gonna take more beer and whiskey than the world can supply for me to say that.