When cleaning, handling for long term storage, recommend wearing nitrile gloves like from Harbor Freight to insure no transfer of fingerprints, human corruption of the metal. Heck, I wear for general cleaning so my wife doesn't think it is my deodorant which is ok by me but not so much for her!
This all sounds like good information.
Not sure why, but I believe I would email the firearms' manufactures and request recommendations for proper long term storage.
I have stored them oiling them and wrapping them in the plastic food wrap and haven't had anyone the ones not being use to spot or any type of damage to them I've had them wrapped for over 3 years and they still look fine