My predicament is that I can't find a decent mtb shoe under $300 but I've got an awesome pair of high end Lake road shoes sitting there doing nothing that I'd love to use. I'm seriously considering throwing on my super light Look road pedals and getting after it. The only real consideration is getting them mucked up by walking in dirt. So has anyone done this and, if so, how much of a concern is getting them dirty as far as usability goes?