Boiled oil has been highly recommended as a cure for dampness caused by absorptive bricks. Its efficacy is due to the fact that it fills the pores of the bricks. It should be applied boiling hot, and rather lavishly, with a large paint brush or even a Turk's head brush. A dry summer day should be chosen, and if possible, a time when the wall is warmed by the sun. The coating should be renewed every two years. It may rather discolour the brickwork if the facing is new stock or terracotta bricks, but will hardly be perceptible with old or common work. A small area should be tried at first, so as to afford some idea as to the ultimate appearance of the whole.