Mustard seed plasters and poultices are a trusted old fashioned remedy for chest congestion and coughs. To make a mustard poultice use a handful of mustard powder to a handful of bran, make a paste with hot water, apply hot. To make a mustard plaster : To every handful of ground mustard add three parts wholewheat flour. Mix into a pliable paste with hot water. Then further add two teaspoons of vinegar to one cup of the mustard-flour mixture. Spread on a piece of cloth and apply hot to the chest. To help guard sensitive skin, add the white of an egg to every 1/2 pint of mixture.