Just about anyone who's put time in at a wet lab has worked with acids, even if only to pH things. Indeed, I was dissolving things in hydrochloric acid back in my high school AP Chemistry days. Some of my more experimentally-minded classmates decided to test the effects of acid immersion on a cockroach that they found (I went to high school in Florida, so test subjects were plentiful). I was not privy to their results. I am, however, familiar with the effects of sulfuric acid on one's pant legs, thanks to some unfortunate splattering in my undergraduate organic chemistry lab.
I've been known to refer to my graduate program as "the neuroscience frat" for our propensity to close down any graduate school event that involve free drinks, the fact that we've purchased entire kegs for departmental mixers, and the more advanced candidates' fearsome skills at beer pong. That being said, I am usually smart enough not to go back to the lab after partaking of these festivities. Usually.
On occasions when I've been working with bacteria or with human blood and/or saliva samples, I have washed my hands before using the restroom. And then again afterward. I tend to wash periodically throughout the day, even when I'm not eating or excreting. If you ever need some hand cream, your friendly neighborhood life scientist probably has a stash to ward off the skin chapping that this can cause.