I use bore stores for the handguns because that way I can stack them.
But, the whole house is air-conditioned (humidity controlled) and I don't live near an ocean.
The safes have goldenrods in them and I'm pretty good about wiping things down or even waxing with renaissance wax for longer term storage.
Even so I'd be afraid to use traditional vinyl or leather gun rugs because they could trap and hold moisture.
I saw nickel Python that was inherited by a friend ruined by being stored in a holster for 10 years. It was corroded even though it was a in a dry drawer the whole time. It was obvious that the leather had wicked and retained whatever moisture there was and held it in contact with the Python. Really sad turn of events, but a good lesson for me.
/c