This tip I learned from my days as a janitor and housekeeper
When opening a can of cleansing powder, don't fully remove the sticky tab that covers the holes on the top of the can. Lift it off and place it over half the holes, leaving half covered, half open. This way there is less waste, less gritty residue to rinse and less product washing into our waterways. This trick is especially useful if young kids want to help clean the bathroom!