You shouldn't need to hone that. First scrape with a razor then try a mild acid. Sulphamic maybe or phosphoric. Do a drop test first to see if it etches because it may have some calcium content as many of the black "granites" will. You may need to replace the grout. If so this would be a good time to allow to dry, while the grout is gone, scrape it all the way out.

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> On Jan 22, 2018, at 6:15 AM, csantospago@gmail.com wrote:
>
> Hi partners,
>
> Looks like efflorescence from water damage. There was carpet over this and a pipe burst. I think it’s absolute black honed threeeights inch tile. My guess is I can grind it off and re-hone it. What do you think?
>
> Thank you,
> Chris Santospago
> Restoration by design stone
>
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