The haze you are experiencing on the surface of glass is most likely calcium deposits that have etched into the glass over time. In Denver, Colorado, we have hard water which can add to the problem. Cleaning the glass at this point can be a catch 22 – you can use harsh or abrasive chemicals to remove the calcium but you may further damage or scratch the glass in the process. You can always stop by L&L Glass and we can sell you a range of products that we use to remove those hard to clean spots on glass.
If your glass has absorbed the water spots into its porous surface and you have tried all of the above cleaning methods without success, you may need to replace the glass. To prevent the replacement glass from suffering the same fate, have the glass professionally treated with Diamon-Fusion before installation.