The Best & Fastest Way To Clean Hard Water Glass Shower Doors

 I've been searching for a good way to clean residue left by our very hard water from our glass shower door.  After trying multiple products and lots of searching and some trial and error, I found two that work great.  You can see a side by side test below- I let the hard water buildup get very noticeable (it is For Science, after all!).  The products I love are Barkeepers Friend powder (apply a little bit with a wet rag or sponge, scrub all over, then rinse).  After, I sometimes give it a quick second clean with window cleaner spray (like Windex) and microfiber cloth.  The other product that does an awesome job is CLR foaming bathroom cleaner.  I generally don't like cleaners with a strong chemical odor but I find this to to be pretty mild and, for what it's worth, says on the label "EPA Safer Choice."  You can see in the comparison both Barkeeper's Friend and CLR do a great job, and to compare, the window cleaner does very little for the hard water stains on its own.  

BEFORE:

DURING:

AFTER: