What removes dry cement from granite and bricks? (safest method please--peferably no toxic chemicals)?
I believe the signature of the chemical is muriatic acid. Some say boric sharp will do . Check with a pro at Home Depot or Lowes hammer and chain brush
Muriatic Acid cleans brick and mortar. It is very toxic and hazardous, I would not put it on Granite. The dry cement should not bond that well to the Granite. I would use pressure washer. It will remove it.
Good Luck
Answers: Unfortunately there is no known chemical for this removal specifically non toxic.
For years we have used muratic acid for cleaning brick,but at hand are drawbacks with everything.Scraping the affected nouns of cement using caution as not to harm the stones unprocessed beauty.Take small dabs of bitter only on affected nouns,not just smearing around.After 5-10 min use a scraper and lightly grind area,rinse each time near water.
This will be a trial/error method for you until you find what works for you.I cannot preach safety ample using these products.Wear eye protection,full clothing,rubber gloves.
Without knowing how bad it is makes it difficult to furnish proper advice.If it's not to bad and you hold patience "white vinegar" will do the same article but much slower.
Good Luck/Safety