The lifts are awful. The escalators are just as bad. Apparently the nastiness the escalator maintenance crew deals with is pretty fetid stuff [1]. Well that's what you get with people who find the bottom of an escalator the coziest place to sleep. It's a shame for both the homeless and the system. But yeah, dont touch any surface within the system unless you're prepared to wash thoroughly

[1]http://m.sfgate.com/bayarea/article/Human-waste-shuts-down-B...

Interestingly, I have seen only one place where there is a sewer drain in an elevator (this is quite near where I live, in an administration centre of modernist concrete design). Judging by the smell, it's very necessary.

Never thought how it works, but I presume the elevator needs to have a storage tank underneath the cage, and that needs to be emptied regularly.