David, I heard Mr. Clean Magic Eraser is amazing for that. In the past, my husband used traditional glass cleaner and a razor blade. It took forever, but it worked. Then when he is done, he uses Rain X on the glass to repel the water. It still has to be done ever 6 months, but it stays looking great. I will see what else I can find to help you!

This formula doesn´t work on glass shower doors that have had hard water stains and calcium deposits that obscure the clarity of the glass. None of the store bought formulas work. What do I need to do to eliminate this stain? Thank you!