I had to face this issue of long term storage twice. Once when I lived in NC and had to deploy for 9 months and once when I resided here in MA, but had to live temporarily in CT for nearly two years due to the job.
In both instances, I removed the wood grips from my blued guns and essentially soaked them in CLP/Breakfree. I then sealed them up in a plastic bag and boxed them up. They held up fine. Someone told me as long as I can keep the oil from drying out, the guns should be fine. A better solution is gun grease, that stuff is a bear to clean off.