None of them are hemmed, because they don’t fray. If you’re worried about it, try gently rubbing at the edge of it. Threads won’t come off in your hand either. Microfiber is just the size of the thread used, these are 100% polyester and completely machine washable.
I’m gonna go ahead and assume the question was asked in good faith and answer it the same way.
If your washing machine is working, there should be no fecal matter left on the clothes after washing. However, many clothes lose color over time due to a number of factors, one being the dye slowly bleeding into wash water each time you do laundry. Many black dyes start to look orange or brownish as they fade, and two socks won’t necessarily fade at the same rate. The only way to put the color back is to redye them, which might not work depending on what the sock is made out of.
I wouldn’t worry about poop, these are clean, just faded . However, if you want to have 2 black socks, you’re gonna have to buy a new pair.