To stain a brick wall, brush the surface with a soft brush, vacuum away all particles, wash and rinse the wall, and apply the stain with a paintbrush in thin layers. Paint only the bricks to avoid staining the mortar, or use broad strokes to cover the whole surface.
When preparing the brick for staining, use only soft-bristled brushes and non-ionic cleaning solution to avoid damaging the brick surface and mortar. Rinse away all loosened debris and cleaner before staining. Protect surrounding walls and floors well with tape and drop cloths; stain cannot be washed off.
Mix the stain according to directions, and test it in a discreet area before applying it to the whole surface. When applying the stain to the brick surface, correct any runs or drips as quickly as possible to avoid leaving permanent marks.