While were on about white powder, a few years ago now i used to have a tropical marine aquarium. With the corals i kept it ment regular dosing with various white powders to keep the alkalinity, calcium levels in check.
One evening whilst i was weighing a good kg of the one such powder there was a knock at the door, i opened the door to find a couple cops enquiring about some disturbance in the area a few nights previously.
Well i invited them in, and saw the look of horror on their face when they saw all this white powder being weighed on my digital scales lol. Before they could say i word, i just said, "No it isn't what your thinking " and promptly showed them the aquarium, both had a good laugh about it.