To make a mustard plaster take equal parts of mustard and flour; stir together with a little warm water, just sufficient to make it into a thick paste. Spread it on a piece of linen that is large enough to fold over and prevent the paste from touching the skin. Apply the plaster to that part of the skin that it is desired to irritate.

Ginger plasters may be made in the same manner, as mustard plasters, and produce the same results and do not blister.