SwordAngel wrote:
Hello,
My driveway is paved with red and gray bricks. Due to a porcelain tile
laying project on my front door stairs, some of the bricks got stained
with a diluted mixture of Keraply (R) (an acrylic latex dry-set mortar
additive) and porcelain powder (from tile cutting). How do I clean up
the stains? I called Mapei, the manufacturer of Keraply, and the
technician who answered doesn't have a sure solution. He suggests,
however, that hydrochloric acid (a.k.a. muriatic acid) may do the job
but that I should check with a masonry/brick laying expert.

Would somebody know the answer? Would vinegar also work? (I know that
vinegar is a much less potent acidic solution than hydrochloric acid,
but I simply have way too much white vinegar at home.)

Some acrylic latexes are kept in suspension with ammonia based systems,
so try some undiluted household ammonia first and scrub vigorously. If
that is ineffective, then switching to a strong acid should be tried
next. Vinegar is too weak to be at all effective. Oxalic acid, a common
component of old fashioned auto radiator flushes ought to work better,
though slow. It will have less effect on brick mortar than
hydrochloric, which you may still have to apply as the last resort.
Good luck.

Joe