Oxalic Acid

[Guy B]

You may need to use a HF acid, alum. brightner is what I use in some applications. This may take the rest of the sealer up.

[plainpainter]

The few times I took rust off of foundations with OX, it always left an area that was much lighter than the surrounding concrete in the pattern of where the rust was. And it didn't matter if I sprayed an area much larger - only where the rust stain was - it becomes much lighter. Part of doing this business is grounding the prospective customer about the results. People equate clean with looking brand new, you have to educate them.

[jefferyjacobs]

What do you spray it with? I would like to start spraying all the concrete I do or at least have a upgrade of "concrete brightning". Can you spray it with a sureflow or a Fatboy?

[GrimeBusters]

I use a quality pump-up sprayer like a Chapin http://www.chapinmfg.com/ShowSprayerA.asp?ModelNum=1949

[Doug Rucker]

Anybody else rinse after applying Ox Acid?

[Bill Booz]

Yes, we always rinse all chems on the ground level before leaving a job. There is Too much risk associated with leaving chem for me to sleep good.

Sorry, I don't really have a solution to this one. I can't see a pic?? Did you post a pic?