“My father told me that during the Korean War they would make coffee by boiling water, adding coffee, then adding a pinch of salt that would make the grinds sink.”
My Dad told me the same thing except that where he was had to make it himself...in his helmet. Filtered it through his handkerchief. Then he rinsed out the helmet, filled it with water again, and shaved. Sometimes he used the coffee to shave.
The pinch of salt trick does work when you have really bad coffee and no chance of finding good coffee.
It does wonders for Maxwell House and Folgers.