An old way of getting rid of a cough, cold, or congestion is something my mother used to do for me when I was little. You make a mustard plaster from dry mustard, water and flour. You are supposed to rub it on your chest and it makes you sweat so you can get better faster.
I had also never heard of this before my grandmother telling me about it but after looking it up online I found that it is a commonly known folk medicine belief. There are many websites that explain what happens and how this remedy works.