CLEANING BRICKWORK
Paint splashes from previous careless work can be removed with a chemical paint remover. The paste type is best as it won’t run down the wall.
This will only strip off the surface paint, however, and some will have soaked into the brick. You may be able to remove this with a wire brush, but if not, apply a poultice of whiting and ammonia kept in position with a piece of polythene taped down at the edges.
This will leave a light patch which can be disguised by rubbing with a piece of old, dirty, broken brick. By the time the brick dust has been washed out by rain, natural weathering will have evened out the tone.