I use this stuff on my car windows as it doesn't have ammonia:
http://www.invisibleglass.com/here are the windexs that are amonia free:
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