I live in a hard water area (Central Mexico). We have a whole house water softener. I have glossy white ceramic tile in my shower. Well, it was glossy. Despite regular cleaning, hard water spots dulled the gloss to an unsightly mess...I mean, really nasty hard to remove layers of spots on spots. I tried: EVERYTHING short of dynamite: including baking soda, vinegar, commercially available spot remover, industrial strength 16% vinegar gel, left on for hours, agitated, rinsed, dried.... No real improvement.

Recently I found the Holy Grail for removing the spots: wet/dry sandpaper, used wet on wet (320 grit). This is the only thing that made a noticeable difference. Now the tiles feel smooth again, and while they aren't dull, they also aren't glossy. In areas where water never reaches, I can see how the tiles were originally. I'm wondering if anyone has used car wax (like Turtlewax paste or liquid) on their shower tiles? And if so, what were your results? I'm hoping to 1) create a higher glossy shine and 2) create a water barrier so that new spots don't form so fast. This is only on the shower walls, not the floor.

It's hard to get a photo that shows the issue. However you can see water spots on the window (those are minor compared to what I'm trying to eradicate. I'll have the glass replaced and the metal repainted, but I can't tear out this tile.