It's called optical hazing and is super common with vitrified porcelain. Diamond encrusted pads MAY do it but start very fine and use a lot of weight.

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> On 13 Apr 2014, at 4:43 am, Stephen Webb <stephen@newlifemarblerestoration.com> wrote:
>
> Customer has a recently installed high gloss Italian porcelain tile with spectra lock epoxy grout. The problem is hazy splotches first thought to be residue from the grout install. It has the appearance of  fogged mirror. I tried polish, stripper etc with no effect. then I looked at it through a magnifying glass and could see the foggy areas have more open pores than the glossy areas. Could anything in the install have cause this? Can porcelain be polished and with what? Customer is going to pull extra tiles out of storage to see if the problem was preexisting.
> Thanks
> Stephen
>
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