Leupold posted an interesting series of photographs to their Facebook page showing one of their scopes that had been found in Idaho after being lost 11 years in the wilderness.
The scope was lost by it's owner, along with the Weatherby Mark V rifle it was mounted on, at 4,000 feet of elevation. The rifle shows it's wear of being exposed to the elements for 11 years, but the scope itself looks in great condition. Being constructed of aluminum and not steel is likely what has saved the scope from any type of corrosion.
What's really interesting is that after 11 years of being exposed to all types of weather the scope still retained it's seals, and was completely fog free and functional. Quoted from the Leupold Facebook page:
11 Years of Surviving the Idaho Wilderness:
This Weatherby Mark V was found in Idaho at 4,000 feet of elevation. It was brought into a sporting goods store where it was later identified by the owner as the rifle he’d lost on a hunting trip 11 years earlier. The Leupold 2-7 scope is still fog-free and fully functional.This is the kind of marketing story that's excellent for scope manufacturers and is a true test of any optic, one that this Leupold scope has passed.
Source post from Leupold's Facebook page.