Granite backsplash

Okay last question:

 

I also had someone do a backsplash to coordinate with my countertops in matching granite tile.  We used both Baltic Brown (to match the countertops) and accented it with galaxy black.  When the backsplash was grouted there remained residue from the grout/sealant on the tiles themselves.  Most of it cannot be noticed but, if you feel the tile, you can feel the roughness of the grout  and there are several areas in which you can see a dullness.  What can I remove this with?  I tried removing it with a scraper in an inconspicuous spot...however, it appears that it scratches the surface so I did not proceed with that tactic.  I also heard I could remove it with hydrogen peroxide...that was a crock...it did nothing!  I'm afraid to try anything else unless I know it will not harm the tile.

I'm open for suggestions,

Thanks,

Cynthia