CLR for hard water removal?

This is my first post here, though I have been lurking for a couple weeks now. Thank you all for the great information, it will come in handy when I strike out on my own next month…

Now, I have been reading a lot about hard water removal and the different chemicals being used. Have any of you used CLR? We have hard water here and it works great at freeing up shower heads and the like. Thoughts?

Also, could anyone expound on the method of using a black light to determine tin side?


Welcome Dave. When using a black light you’ll need to make sure you limit the amount of light on the window. If you have to check some glass on a sunny day try using an umbrella to shade the window (great tip I was given by Mike Draper). The reflection from the black light will have a grayish hue when you are on the tin side.


What is the best black light setup? A shop light with a black light bulb? Can you get a black light bulb for a maglite?

Try this - CHNVF4 - Chauvet 6 Inch Handheld Blacklight

Thanks, that looks like a good place for black lights. What do you all think about this item?

BLWUVPEN - Ultra Violet LED Blacklight Pen Light

It is a black light pen light. If it would work I could just keep it in my note pad case.

About the CLR, I am thinking of just getting some and trying it out, along with some of the other suggestions on here. I figure having a few different tools will be better anyway.


Not sure about the penlight. It might not illuminate a large enough surface to be effective.
I also carry a few different chemicals to deal w/ hard water.

Went and picked up some Safe Restore today from a local shop. Tried it out on some REALLY bad harwdwater stains and corrosion. Wiped on, let dwell, rinsed off - then washed window like normal. BEAUTIFUL!!! Good stuff. I also picked up some Winsol CC 550 just in case, but didn’t need it. I sampled a small pane, but the lady didn’t like my price - so now she has one beautiful pane to look at amongst all of the nasty ones. I should have taken pics, if we get the job I will post some photos.

If all that was required was dwell then rinse, then the windows [B]weren’t[/B] “REALLY bad harwdwater stains.”

BTW, corrosion only occurs between panes – in a stagnant environment – not on an exposed surface.

And, if it was a silicate, SafeRestore won’t remove it.

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  1. So I exaggerated a bit, but they were bad, and I applied two coats then used a white scrub pad. Thanks for calling me out.

  2. [B]cor⋅rode[/B]
    /kəˈroʊd/ [kuh-rohd] verb, -rod⋅ed, -rod⋅ing.

–verb (used with object)

  1. to eat or wear away gradually as if by gnawing, esp. by chemical action.
    [B]2. to impair; deteriorate[/B]

I would consider hard water buildup on glass to [B]impair[/B] the life, clarity, and usefulness of such glass. And over time, hard water can lead to etching which would in turn [B]deteriorate[/B] the surface of said glass.


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Steel will rust. Aluminum will oxidize. Brass will tarnish. Copper will patina. Vinyl will fade. Wood will rot. Concrete will crack.

Glass will corrode.

But then again…what do I know?

The chemical reaction required to create corrosion includes a change in pH, which cannot occur on an exposed surface.

Corrosion is a specific term when utilized in the WC’ing industry (as opposed to a dixshunaire.)

So do you have any experience with CLR?

What type of product would be needed for removing a silicate? Does CLR induce the correct reaction for silicates? What does? Wouldn’t anything that can react with silicate deposit also react with glass?

Do we have a resident chemist?:smiley:

For silicates use Safe Restore or Winsol CC-550. Just remember to check for the tin side of the glass w/ the UV light.

We don’t need a resident chemist - we have a resident Larry!:wink:

If there is some mild silicate deposits, ive used saferestore and some steel with a lot of success. Now if you have some heavy silicate deposits, the only thing that will touch that is CC550. If you dont have a black light, test a area on the corner of the pane with a q-tip.

Thanks Big B.

It looks like CC550 is the way to go for the tough silicates…

This may be a dumb idea, but what about something along the lines of jeweler’s rouge? That shouldn’t scratch glass right? Add a power buffer and it should do the trick.

Hey Tony, that’s new for me … so Safe Restore will affect glass if applied on the tin side ?? No wonder why I had a cloudy spot on a window I cleaned the other day, no problem because 90% of the windows in that house are gonna have to be replaced, so owner was " don’t even worry".
If I go back in time even more I can remember a couple of spots on windows where SR was applied, wasn’t as bas as last time, looked like run off kinda stains, no color, pretty much blended in with the glass, but if you looked closely you’ll notice.

I was thinking in ordering some dehazer (sp?) don’t know if that is the product, I’ve seen that somewhere, it was recommended to “fix” stuff gone wrong with CC550.

The Safe Restore may pose no problem on the tin side but it is an acid and if allowed to dry on the surface in direct sunlight you could have issues. I was referring to the CC-550. It can cook the tin side pretty quickly.

I believe jewelers rouge is for polishing soft precious metals.

Research cerium oxide for removal of hard water stains and scratch removal.

Some mechanical scratch removal/glass restoration equipment can be found here.

You shouldnt have any problem taking it off with CC550 and a white scrubby pad and some steel wool. That stuff is pretty gnarly. Just be careful. wear glove and eye protection too.

So I take it 550 is a last resort, right? I should try saferestore or some other milder product first?

If I am working the tin side, should I just go straight to the cerium oxide and skip the 550?

Could I avoid using 550 altogether and just use cerium oxide on the tough stuff? I would rather avoid having to mess with harsh chemicals, but I am comfortable with it if necessary.

Thanks for the advise, I will do some research on both products.