Meguiars glass polishing compound is a fantastic product for cleaning / polishing windows. It cleans the glass thoroughly and can in some cases remove small micro-scratches, restoring great clarity and depth to the glass.
Note that there is abrasive in the product, so it should not be used on top of window film and similar.
You can greatly benefit from using Meguiars Glass Sealant after treatment with this product to give your windows a good water-repellent effect; for daily cleaning of the windows, we recommend Meguiars Perfect Clarity Glass Cleaner.