Is there a substance that is hard (ideally abrasive) in solid form but would dissolve in water? doing some research for a dishwasher / dish cleaning product and interested in any compounds that could be fashioned into a brush or other abrasive form and then dissolve and wash away with the water cycle?
A usual cleaning product that does not pose any health hazard and that is easily washed away is sodium hydrogenocarbonate (aka baking soda). I use it myself, and it works a charm in the kitchen!