Now I can't tell which are the ones I wore.
You mean, they both pass the smell test, or they both fail?
What worries you are having then? Is no problem! You are lucky you are smelling so good the feet.
Oh. On first read, I thought the aliens comment was meant to express how uncomfortable you'd be if you (by accident or necessity) subjected others to something you usually consider objectionable when you're on the receiving end of it.
We can conclude that I suck at reading.
That would be another way to tell which ones you've worn. Unless you have tiny girly little feet that make no impression in your socks.
Hmm. I was going to go with the stretched out idea too, but, thwarted again!
Does it creep you out to think you might wear dirty socks unknowingly?