Kandla grey lemon juice staining - Warning to others and open to advice

[Karanbajwa]

Hi all I wanted to inform others about a experience I had.

I had a few orange droplet splash marks of mosskiller on kandla grey riven stones.

I applied a few drops of lemon juice to the stains and brushed and then rinsed off with water and they seemed to disappear.

A few days later there are faint orange-brown Mark's wherever the lemon juice was applied which I believe may be acid staining. As Tony mentions they are actually more noticable then the initial small droplet stains

I was aware of acid staining but it is not something I thought would happen with weak citric acid.

Do anyone have any product suggestions? Strangely scratching the stains with a thumbnail seems to slightly fade them?

[Tony McC]

Try a *good quality* rust remover, and if you have the opportunity, treat a single instance in a discreet corner by cleaning the WHOLE of the flag with the rust remover, just in case it has a subtle lightening or darkening effect that would be really apparent if you just did a 'spot' treatment.

[RAPressureWashing]

Citric acid (Lemon juice ) isn't going to be strong enough or the right thing to use on iron phosphate staining, can you post a photo of the staining, it is possible to remove them, as long as they are not to deep into the stone etc.

[Karanbajwa]

Hi Tony and Roger. I much appreciated your responses thank you. Unfortunately I did not get a chance to take photos.

I did take the advice to use lithofin rust ex. (The one which turns purple on contact with rust) And that seemed to work well after 4-5 goes.

Interestingly I also tried the lithofin rust ex on a few yellowly bird mess stains which had persisted for months. It seemed to react (turn purple) with those too and helped significantly lighten them. I found it interesting, perhaps the bird droppings too were acidic and also caused a mild rust reaction.

Once again thank you too all