Hi Kathyrose - welcome.
I have the sliding type, and a dog that loves to leave nose prints. For eight years now I have opened the windows as far as possible and then cleaned where the screen no longer is. For the rest of the window, about once a a year I "pop" out the screens, being careful not to bend the frames. One warning though, you have to have patience getting them back in, and must start by making sure you are putting the top on the proper slider.