Mustard Bath for the Feet
It gives relief to a bad cold in the early stages, to soak the feet in warm water, in which you have put half a tea cup of salt and two tablespoonsful of pulverized mustard, and to drink ginger tea. You may keep your feet in the bath for half an hour, and then retire with a warm soap stone wrapped in a cloth and placed near them. A soap stone, the size of a brick will, when thoroughly heated, keep warm till morning, and is invaluable for an elderly person or one that suffers with cold feet.
Source: Domestic Cookery, Useful Receipts, and Hints to Young Housekeepers, Elizabeth E. Lea