Not without damaging the masonry. It wouldn't matter at all if it were a standard municipal building, but this building is protected. If Banksy stenciled another My Chemical Romance poster on the Frank Lloyd Wright Unity Temple in Oak Park, you'd get a flavor for how complicated the discussion would be.

The job requires methods more akin to restoring a painting after a knobhead splashes it with ketchup than a pressure washer, as it is a historically preserved building.