Here’s an old fashioned remedy that I use to relieve my Arthritis Pains. I make what you call a Mustard plaster.
To do this you need to mix together 2 parts flour with 1 part Mustard powder, then add some water to make a paste. S
pread it on a clean cloth of some sort, fold it in half and press against the skin. Don’t put the salve directly on the skin since it can burn.
You can also use this to loosen phlegm or for Sore Muscles