It depends on the brick, Ive seen pros ruin beige brick on a million
dollar house. Detrich makes chemicals- acids for cleaning. Sherwin
Williams sells them. Or it could be as simple as a 20 % muriatic
solution - powerwashed. Plus acid burns lungs, plants and eyes and
skin. Is it hard glaze brick, medium,, what year, all sides of house.
Cant SEE it cant give honest safe advice, are you sure it isnt mold or
easy dirt. does it brush off, Lotta questions