If it is a “porous” surface, then ELEPHANT SNOT Graffiti Remover is the right choice for the job. Elephant Snot is the workhorse for the most difficult of porous surface removal requirement. Elephant Snot penetrates deeply into concrete, cement, brick, grout, stone, virtually anything porous to dissolve and loosen all types of tags. In many circumstances, simple water hose pressure will do the job, though high pressure water is recommended.