[1] Scouring powder is used to clean encrusted deposits on hard surfaces such as ceramic tiles, pots and pans, baking trays, grill, porcelain sinks, bathtubs, toilet bowls and other bathroom fixtures.
[1] The abrasive can be silica (quartz, SiO2), feldspar (such as orthoclase), pumice, kaolinite, soapstone, talc, calcium carbonate (limestone, chalk), calcite, etc..
[1] The Bar Keepers Friend scouring powder has oxalic acid instead of the base, which makes it effective against rust stains rather than grease and other organic dirt.
Bathing in ancient Greece and Rome started with rubbing the body with fine sand mixed with oil or other substances, and then scraping it off with a special curved spatula, a strigil.
Scouring powders have been marketed with many other companies and brand names, such as Ajax, Bon Ami, Radium, Comet, Sano, and Zud.