Let your readers know that Drano is not an acid and should never be combined with muriatic acid.'' Excellent point, Dr. Mitchell, and appreciated by the handyman. At least the handyman did not suggest combining the two materials. In fact, one should never combine two materials designed to do the same thing, or for that matter, any two cleaning materials. Q. I have heard that muriatic acid will remove cement that got brushed onto a patio when the bricks were remortared. You heard right, but your other questions are interesting because there are no directions on the acid bottle as to how to do the treatment.
Muriatic acid attacks the lime in cement and mortar, and that is how it removes it.
Brush on the solution with a paintbrush or pour it on the smeared cement or mortar. Scrubbing with a scrub brush or wire brush will help remove stubborn spots. Repeat as necessary. Let the rinsed area dry off completely before repeating.