Raw masonry surfaces are always a favourite target of taggers. Try a solvent remover, waiting 3 to 5 minutes before agitating with a wire brush then washing away from surface.
If the area has heavy graffiti, a paint stripper may need to be applied to the surface when dry, waiting 3 to 5 minutes before agitating with a wire brush and washing away from surface.
For surfaces of masonry, using a pressure washer set to low, such as 80 PSI, is the best setting. Other fine-tuning techniques include not setting the spray nozzle to a narrow setting, for this may cause etching of the graffiti on the surface.
Always exercise standard safety precautions when using pressure spraying in graffiti removal. Once the pressure spraying method is chosen, make sure that all the proper settings are made in order to prevent injury both to the operator and to people in the surroundings, as well as damage to the property.
Be familiarized with the operating instructions of the pressure washer manufacturer before attempting to work with it. For delicate and old masonry surfaces, do not set the water pressure to more than 500 PSI. For optimum graffiti removal, angle the sprayer nozzle to about fifteen to fifty degrees from the wall. Never set the sprayer’s nozzle directly on the surface; this will more likely damage wooden and masonry surfaces.
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