Just some facts to complicate your descriptions: The sweat gland evolved from the kidney, thus - sweat is essentially watered-down urine (explains the high salt content, plus the yellow color sweat stains). That being said, just for sensationalist value, 😉 I doubt there exists any real risk of contamination of any sort from touching hair or the lav handle. Yeah, it's disgusting, but from a medical standpoint, you're okay.
Then again - I have no problem walking into a lav with socks. (Honestly - yeah, it's a bit gross, but fresh urine is completely sterile, contains no bacteria, and if one steps in it, the worst one encounters is bacteria producing nitrogen and ammonia in breaking it down). But - then again - I'm trying to become an ER physician, and this stuff doesn't really scare me 😉
I hoped you enjoyed the DC-9. I flew on two for college visits senior of high school from DTW - CMH. Loved it.