Well don't know whether this is a spoiler but Kal-El grows a beard into his early adult life and doesn't shave it until he leaves the Fortress wearing what we would call the Superman Costume. So the big question. How does he shave? His skin in invulnerable. Nothing can touch him. Needles bend against his skin. A razor would simply break. How does he do it? Kevin Smith posted the most plausible theory that I can think of which is that he broke a piece of metal off the ship that brought him to Earth and uses it as a makeshift razor. Shooting Heat Vision (Which is raw solar energy) into a mirror would simply destroy the mirror and the wall it is on so I don't pass that theory! Post your theories here!