I store a few in their holsters, but check them often. Never have had any problems. But the humidity is controlled.
By the same token - every few years I may oil them. Again no problems.
Many pistols I have stored in Sackups - which are like socks. Takes less storage space. And for pistols, one size sort of fits all pistols.
Sackups are Silicone treated to prevent rust and to wick moisture away from your firearm.
They are also available for rifles, shotguns, knives, golf clubs, etc.
http://sackups.com/
In essence they are the same as the borestores products.