A blog reader submitted the following question to us: “After removing the grout from our natural stone polished tiles, and before sealing, they were a couple of small stains which were probably water. We used Cillit Bang to remove this but has made worse. Are there any products that could remove this?”
And our suggested course of action was as follows:
” Sorry to hear of your predicament. I am assuming that what you have is a ‘polished’ natural stone, such as marble or limestone. Let me first tell you that you are not the first person to do this by a long way. The product you mention contains an acid and although acids can help break down cement and grout, they should never be used as cleaners on acid sensitive stone, which is what you have.
What I suspect has happened is that you may or may not have fully removed the cement residue, but in attempting to do that, the cleaning product has etched the polished surface of the stone. Basically the polish is created by grinding and rubbing the stone at the factory with diamonds or silica carbide blocks, working first with coarse grit all the way down to the finest, just like using different sandpapers on wood to get a smooth finish. With the surface now super-smooth, it is very flat and reflects light very well, creating the full color reflection and high gloss finish of polished stone. The acid in the cleaner has instantly reacted with the calcium carbonate in the stone, eroding it away irregularly (eating small chunks of the surface) this has the effect of putting it back into a very rough and unpolished state.
So what can you do? well it depends on how bad it is and how wide spread. If you have only a few spots then you may be able to re-polish with a hand re-polishing cream such as Renue. If the etch marks are deeper than that, then you may need to have the stone diamond polished again – this is usually a job for a professional.
If you feel it is hand polish – able then you still need to get all the grout staining off. For this I would recommend MicroscrubTM – it is a safe abrasive cleaner that will help remove grout deposits without harming the stone. Do this then examine the stone to see how bad the etches are. If however you feel that there could be a significant amount of etching all over, then cleaning the grout is not so much of an issue, as if you have to resort to calling in a stone professional, the process will also remove any grout residue.
Let us know if we can be of any further help.”Copyright Ian Taylor and The Tile and Stone Blog.co.uk, 2013. See copyright notice above.