Hair doesn't get old or moldy.

As a total side-note, hair actually can get moldy. I didn’t know that was a thing until recently, but my best friend’s mom was in a nursing home and she (friend) wasn’t allowed to visit for almost two months (because of the pandemic, obviously). When she did get to see her, she found (and took photos of) actual goddamn mold in her mother’s hair at the back of her neck because her hair hadn’t been brushed or washed and moisture from sweat had just been allowed to... well, grow mold. (She obviously moved her mother out of that facility immediately, of course.)

But in normal circumstances, of course, that doesn’t happen. Just sharing a horrible “that’s actually a thing?” fact.