Assuming you meant vinyl windows, the first thing to keep in mind is to never use paper towels on them. Never, ever. Paper towels are made from wood pulp and they leave tiny scratches in the vinyl every time, to the point the vinyl window will form a haze and eventually turn opaque/yellow. Resist the urge to clean your top's vinyl windows at the gas station, doing so will eventually and literally ruin them.
Instead, use warm soapy water and only something like an old soft cotton towel, t-shirt, or if you want to get fancy one of those microfiber cloths. Use plastic/vinyl window polishing products like Meguiars or Novus to get rid of scratches or haze. Few automotive stores carry any of those but nearly any boating supply store will since boats commonly use plastic/vinyl windows. Novus is a good foaming aerosol vinyl window cleaning product but I'm not sure what benefit it has over a good mild soapy solution.