Natural stone cleaning

This morning I cleaned a large office building with natural stone walls. They were stained with algea and red clay. I found a rust remover from walmart which broke down the stain but left a yellowish color on the rocks. Does anybody have a recommendation on the best chemical to treat red dirt stains on natural stone that wont leave another color stain in its place?

W/O a pic you’re not going to get anything but guesses, What type of natural stone? Got to give a lot more info. We’re pretty good, but not psychic, lol.

I found a masonry cleaner online for rust which may due the trick

The picture above is shown after I washed the big stain with a rust remover I found at Walmart.

Wanted to reopen this thread after a job I finished this week. I honestly wasn’t sure how difficult this was going to be, but it went very well. Used my ds injector and rinsed. Had to get my 12v for the top part of the chimney for a hotter mix.


1 Like

An acid based cleaner should do it… like a rust remover

Test spot, dilute and go stronger as needed