Watching Man of Steel right now with my son. He wants to know if Superman sheds cells or if he retains all of his cells from the time he gained his powers and only produces new ones. And if he does shed cells, do they retain Kryptonian properties.
Movie 4, Superman donated a single strand of Hair to a museum.
Lex Luthor needed bolt cutters to steal it.
The hair was used to make the Nuclear man.
...
Human Hair is supposed to be dead, even when it's still attached to us.
Kyptonian hair should incrementally lose it's super Kryptonian properties as it gradually loses it's solar charge over the course of 5 days. If in this case, that it seems like months or years later, that the museum super hair is still constantly processing new sunlight to achieve finite amounts of new invulnerability, then the super hair is still alive, and Superman is immortal and cannot die. If his hair is still alive and immortal, its growing forever. In a thousand years, or less, all of Earth will be Clark's beard.
(Getting gross.)
If Kyptonians shed skin like we shed skin, but super invulnerability stops that biological necessity, then Kal is going to explode like a cluster bomb intermittently, and pounds of super dense skin is flung outward of his dermis after the pressure built to a boiling point, and Superman shreds Metropolis, or his wife.
Relying on hydraulic pressure of urine, you would think that superman would need to be containing literally tons of water in his belly before he could part his urethra to express his waters. Logically therefore, for every cup of coffee Clark drinks, he would have to also drink a lake, to avoid a urinary track infection. If he drinks a polluted lake, or another damaged source... Could he clean Flint Michigan with his super kidneys? Can he cry?
Super toe nail clippings would be a very valuable building supply for anyone who knows the secret identities of the Super Family. In Thor there's a Norse longboat made out of toenails. I'm thinking about building space ships. Batman, Lex Luthor, Green Arrow, and other JLA billionaires probably have aerospace divisions, and they fight over Clark's bathroom trash.
Snot contracts over time. A wet nugget you wipe under your desk gets a little smaller and a lot harder as it dries out. As super snot stuck to the underneath of Clark's desk contracts, its going to rip his desk to pieces. The janitor may get suspicious.
Would he need a chisel to get sleep out of his eye? He uses a curved mirror from his space ship hull to shave with heat vision. If Supes burns off the top layer of skin every month, then maybe Clark or Kara won't explode. Which means that none of them can have body hair, or scalp hair or facial hair or pubic hair, to avoid exploding.
Superman is bald.
He wears a wig.
