I wasn't as clear as I should have been. I'm not worried about cleaning the lens, more concerned about it gathering a bunch of lint and dirt during the day if I'm working in a dirty environment. I was wondering if there was a good way of avoiding the biggest part of the dirt and wondering how dirty can it get before the reticle is useless. When in the holster the optic makes a nice little shelf, with a lip around it, for things to fall into and get caught. Bigger stuff will fall out when drawing but dust and lint may hang around and block or obscure the reticle.
Maybe It's a non-issue. I just figured someone here has a RDS on their EDC and carry in dirty environments.