I think I have set in stains on/in my shower door (two door, full-length glass slider). I’ve scrubbed, scrubbed, scrubbed. I’ve used bleach, windex, foaming cleaner, to no avail. The same pesky spots remain. I’ve even tried to use a scouring pad to get them off. Doesn’t work. What is it? Does anyone have a solution that works? Is it too much to ask that my doors look like clear windows? Mom – what would YOU do?