Way back in the late 70's the LGS owner told me he would take the grips off a gun, put it in a plastic bag, then hose it down with WD-40 and seal it up and store it. That's just what I did, for decades. I would wrap the package in newspaper and put it in a safe deposit box in the bank.
Worked fine. I did have to clean the guns before use but that just taught me how to clean guns.
I did this back when I was single and didn't live in a secure abode. At times I lived in cheap trailer parks and such. My home is more secure now, but I'd do this again in a heartbeat if need be.