Overtime, bricks can become stained with efflorescence, the flour looking chemical, moss, dirt and many other types of grime.
– Wash thoroughly with soda soap.
– Wash thoroughly with soap solution mixed with household ammonia.
– Clean off with wire brush. Paint any remainder with spirits of salt, leave for a while and wash off with clean water.
– It is best to paint the brickwork for best results. You can get suitable brick-coloured paints.