The oven thing is actually the classic way to remove the skin from the kernel, not the shell. Removing the shell is a simple hammer or nutcracker proposition; it’s the skin that’s hard to get off. Shell them, then roast them. The skin becomes dry and flaky in the oven, and rubbing them vigorously in a towel will flake off most of the skin, but some patches will stick tenaciously anyway. That’s really just a cosmetic annoyance, as there’s nothing unsavory about the skin.