Edit: Well reading up on their site, apparently Windex is safe to use on plastics? I would still use an ammonia free one. Learn something new everyday.The following products do not contain ammonia. They can be used in cases where ammonia is not recommended for use on surface.
Windex® Crystal Rain™, Windex® Multi-Surface with Glade® Clear Springs™, Windex® Multi-Surface Antibacterial, Windex® Multi-Surface Vinegar, Windex® Outdoor Multi-Surface Concentrated Cleaner and Windex™ Outdoor All-in-One Glass Cleaning Tool