If it was stored in the box in a humid environment, the cardboard box could absorb water in the air and act like a "wet box" that the filter is stored in - not a good scenario. I was in Walmart on Friday and looked a a few filters and saw a couple with rust on the base plate ... brand new, and not very old at all.Agree with @Yuk . There's nothing wrong with an oil filter sitting on the shelf for years. Maybe, possibly if it sat there for 10 or more years in a climate that's extremely wet like the tropics or something . . . In a semi outdoor setting like a partially open garage or something. Even then, if it's in a cardboard container, I doubt it would be damaged because the cardboard would absorb a good bit of the moisture.