I am studying to take my pesticide license test, and am trying to plan my business. I have searched for spray rigs, and Most that I find are to large for my current needs. I was wondering what everyone used to spray round-up? Do you clean your tank out after each use, or leave the round-up in, (it would be the only spray used). Reason that I am doing this, is because i mow a few yards with gravel parking lots, and the clean look of a gravel parking lot looks a lot better than straggling grass lines IMO. Any help would do. Thanks in advance.