Camera Lens Cleaning

I have 3 FloodLight cameras. They all work flawlessly. My question: they are exposed to the elements and things get a bit dirty. Cleaning the lights are simple enough: soft terry cloth and water...maybe a mild detergent like Dawn or something. But what about the actual camera lens (that dome-like thing on the underside of the unit)? Would the same logic apply (soft cloth with water and a mild detergent)? I have looked everywhere and keying in 'clean the lens' reveals zero suggestions.