How to remove black substance from white brick?

miszuk

Hi All!

The letterboxes at the front of our property over time has shown this black substance seeping down from the black letterbox cover onto the white brick.

We attempted to clean with water and soap which failed.

We also sprayed on the product "30 seconds, spray and walk away" which is for lichen, moss and algae but that also did not do anything.

Can someone recommend a product to try that can take these black markings off?

Thankyou!

MitchellMc

Welcome to the Bunnings Workshop community @miszuk. It's marvellous to have you join us and many thanks for your question on stained brickwork.

That's quite an unusual staining pattern. If the black staining was simply coming from the letterbox itself, I'd normally expect to see it running along the entire length rather than just in those narrow strips.

Do you have any idea whether there's something directly above those marks that's causing water to concentrate in those areas?

If the algae remover hasn't had any effect, the next thing I'd try would be a bucket of warm water mixed with dishwashing detergent and a stiff-bristled scrubbing brush. That should help remove any surface grime if it's sitting on the brick rather than soaking into it. You could also try a pressure washer.

At this stage, though, it's a little difficult to recommend a specific cleaner without knowing exactly what's causing the staining. If you could upload a few photos of the top of the letterbox and the areas where the staining begins, that would give our members a much better idea of what's happening and help narrow down the best solution.

Please let me know if you have any questions.

Mitchell