In this study, a series of physical and chemical tests were conducted to investigate, evaluate and improve the building cleaning efficiency. Seven different abrasives were adopted for air abrasive cleaning, including copper slag (coarse, medium and fine), recycled glass (coarse, medium and fine) and hazelnut/almond shell (natural abrasive), on a total of eight masonry stones and clay bricks, including yellow and red sandstones, limestone, marble, granite, and white, yellow and red clay bricks. Physical investigations included sieve tests and impact tests on the abrasives, advanced greyscale...