Remove grout sealer from granite countertops?

I recently had granite tile counter tops installed in my home. The installer sealed the grout and let the sealant dry on the granite, now I have a film on the granite tiles. How do I remove that film of sealer. I tried elbow grease and goop and no luck. So, I tries a palm sander with grit sandpaper and that didn't work. Any suggestions???? Thanks