Let me clear this up.
No, I never stated anything like 140 degrees or 5 minutes--but I have written about dunking a scope in warm (not HOT) water to see if it ALREADY has a faulty seal.
This is done in water that feels pretty warm to the touch, but not uncomfortable. The temperature is probably around 100 degrees, and won't harm the seals in any scope.
The warm water heats up the gas inside the scope, whether atmosphere, nitrogen or whatever. If the scope does have a faulty seal, the gas will start leaking steadily from the seal. Once that occurs, the scope should be removed from the water. Because the gas is pushing outward, no water enters the scope.
By the way, scopes are filled with nitrogen (or argon, or whatever) just to be sure there's no atmospheric moisture inside when they leave the factory. The nitrogen is expected to bleed off eventually, though obviously not all will leave the scope. But if the seals remain tight they prevent moisture from entering the scope, even after some of the nitrogen bleeds off.
