I had the same issue. We live in a very hard water area (lime is our big culprit). I searched here for suggestions and tried EVERY, and I mean EVERY recommended cleaner. CLR, an auto glass cleaner I had to special order, vinegar, dryer sheets, steam, blah blah blah. They all did next to nothing.
Finally discovered something that works: High-strength vinegar. I got it at the grocery store, sold with the regular vinegar, in a gallon jug. I sprayed it all over the doors, applied paper towels, and sprayed them again so it would soak for awhile. Scrubbed with a scotch brite type pad and it came off. Regular vinegar had done nothing, it had been like spraying water. The high-strength vinegar was like a miracle. I could actually see the cloudy mineral deposits coming off as I sprayed.
This was after literally 4 yrs of shower door heck. I was so incredibly happy!! I now pick it up every time I go to that grocery store to keep a gallon of it on reserve at all times.
Hope it works for you!
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Fabric softener sheets to keep shower doors clean....go figure!
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