i am constantly amazed at by how many people think windex is a good window cleaning solution. It simply isn't. The best that it can do is smudge dirty glass around and make everything look foggy. If you insist on doing your own glass, do yourself a favor and get a squeegee and put some warm water and a little bit of dawn into your bucket and wash them that way. At least this way when we have to come around and fix the glass it won't be so dirty. :-)