Getting concrete/grout off of glass blocks

As you may remember, I was puzzling out the best way to remove very stubborn (over 100 years old) concrete/grout from precious salvaged glass blocks from my old high school. Muriatic acid was suggested - but discouraged because of the dangers of working with this dangerous liquid. I'm here and healthy to tell you all that I did use it SUCCESSFULLY. I followed all of the safety precautions, used an old plastic tub, added the acid to the water that I had submerged the blocks in. It took two times, but they are gleaming clean.