After 50 years of life, Conrad's windows had seen their fair share of hard water.  Almost all of the windows had a thick film, hard water spots, and were difficult to see out of.  So, I went to my trusty foaming glass cleaner and went to work, only to be sadly disappointed by the result.  Sure, it cleaned the dirt off, but didn't touch the baked on hard water spots.  Out came the Bar Keepers Friend.  It is sold in all grocery stores and hardware stores with the Comet cleaner.  I chose the powdered version (they also have a liquid), as I wanted the extra grit.

After cleaning all of the windows with glass cleaner to get the dirt, dust and grime off, I sprayed the glass down with water, then sprinkled a generous amount of Bar Keepers Friend (BKF) on the wet glass.  Using a microfiber towel, and turning it frequently, the elbow grease kicked into gear.  Rub, Rub and Rub some more.  Circular motion, up and down, side to side, wax on, wax off.  After I thought I had done enough, I cleaned off the BKF with some glass cleaner and went back to work on the areas that still looked like they needed some more help.  The result was amazing.  All of the hard water spots, and even the residue from the rubber seal around the vent window, were gone.  The glass all looks like new.  I can see clearly now.

The Cleaning Agents:

The Target:

THE PROCESS...

Wet down the glass with a spray bottle of water:

A generous sprinkling of the BKF:

The elbow grease:

After final cleaning with the foaming glass cleaner, the final result: