Mother Nature’s interactions with your stucco cause most stains. Most result from concentrated dirty water run off (rain, pollen, dust and organic material) absorbed into the stucco’s porous surface. To clean stucco, start by saturating the entire wall from the bottom up to prevent absorption of dirty water created during cleaning. Use a hard, nylon-bristled brush with mild laundry detergent to scrub the stain. If unsuccessful, move to more stringent cleaning solvents like tri-sodium phosphate (TSP) or Lime-A-Way. As a last resort, try using diluted muriatic acid, but be careful as it can damage plants, some building materials and skin and eyes. If you desire a pristine wall, you probably need a re-stucco. Contact us for a free estimate.