The reason I got to thinking about this is because yesterday I had to remove some kinda mystery spooge off of my Monaco GP cockpit- it had basically hardened to the consistency of super glue, and my best 'guess' on what it was, was that it was spit from someone who'd been chewing tobacco. It had that brownish haze to it. It's the only conclusion I could come to.
Rest assured I washed my hands about 20x yesterday, like some guy with OCD and tissue paper skin on their hands...