Couple Newbie Questions about Oxalic Acid and Hardwater Removal


Has anyone used Pure Oxalic acid for cleaning hardwater stains off windows? How does it compare to Barkeeper’s Friend? Do you have to dilute it with water, or any other special techniqes to prepare it?

Is it still alright to use 0000 Steel Wool with Oxalic Acid or BKF, or does the chemical reactions make abrasion unneccessary?

Also, is Bronze Wool Always fine enough to not scratch windows? It doesn’t seem to be graded the same as Steel Wool.

Thanks all, this is a great forum and I really enjoy browsing it and learning what I can.


Unger Rubout. This stuff works great and is risk free:-

Ask Luke about steel wool. He has great videos on it. Bronze is less aggressive and softer on glass.


Oxalic acid is NOT for hard water stains my man. Thats for rust stains on concrete.

As for the bronze wool just make sure to get it from a window cleaning supply house.

BKF works on the glass just like when you compound your truck when you get ready to buff and wax it.

Its the same principle (in my mind, but that’s just talking outta my neck I got no real proof).

Its nothing thats in BKF as in chemicals that does it, you can get the same results using toothpaste.

As far as chems go, use either the hydrochloric or the other one that is in OneRestore (my brain farted cant remember the chem)

Just need to be careful with both.

Steel wool WILL ALSO scratch glass.
Should test in sunlight in a small area


I prefer phosphoric acid as its one of the few which does not etch glass at standard temperatures , unlike hydrochloric which can easily etch the glass.


I have only had a chance to use the barkeepers friend on hard water and it works pretty good. But just make sure you have wiped off everything on the glass and window sills because if you read the back label it says there is a chance to etch aluminium or other surfaces and I don’t think you want that kind of call back


for hardwater stains… we use 1restore…


How much extra to you charge for that?


we double the regular price.


Nice. How many people usually do a double take when you say that price? I mean it does need to get done so the price shouldn’t shock them that bad. And another question for you, when you go back to the same windows in say the fall or next spring you ever see the hard water coming back? Thanks! :slight_smile:


Most of our clients dont even bat an eye… which always has me wondering if we are too cheap lol…

And so far we have not had it come back! good stuff!


Are you sealing the glass after your removing the hard water stains with the onerestore?


Yes most of the time if the customer purchases it.


If I can I would like to make you a suggestion…

When pricing hard water stain removal always price it to cover the cost of sealing it.
“All in one package.”

After the pores in the glass are exposed by the harsh removal of the stain the glass is more susceptible to future staining.


we usually do just that actually, we are big on packages. Some customers just want the stain removed… ie selling the house, storefront, etc… our sealant is expensive… 1restore isnt that expensive.