It all has to do with chain grease. See one of the BEST Bike blogs EVER, This Guy Knows what I'm Talking About, from a post on her adventures in bicycling in Thailand titled "To Chiang Dao".
(I've run out of material, so all I'm going to do is link to other things).
She also has some great bits on wearing plastic (lycra/spandex) in The Worst Gear Review Ever part II and A Guide to the Tour D'Afrique. As someone who's never liked the feel of polyester or tight clothes, I can relate. Not slamming lycra-wearers (esp. since I guess I did break down and wear it for one of my cyclocross seasons) as I think you should ride in whatever you want.
I came across all this by accident while reading about biking instead of just actually biking. Somehow I found a forum called Tarckbike.com (had to look up tarck) and they have an ongoing Bike Blog thread wherein they make fun of bike blogs, most notably Prolly is not Probably and of course Riv bikes. This Guy Knows..About received a thumbs up. Luckily, this wee little blog is too far under the radar.
The last post for This Guy Knows was Nov 2012, but she did mention something about riding the Divide in 2014.