I make up a plaster with cayenne and salt to cure muscle strains and pains.
I wet a paper towel and sprinkle just a little of both on it, and apply.
The salt is rough being crystals, and irritates the skin a bit, so I make a saline solution and wet the paper towel with that. The cayenne may irritate some people's skin, but it is used for irritated skin, so isn't a big problem.
I even heard of using it on sunburn.) It usually takes 20min to cure pains or strains. I once had a really strained back and leg. The back came from working under a car, laying on concrete, and the leg was sciatica from sitting on a wooden bench after it.
My back hurt from my neck to my foot, and my thigh would hurt SO bad I could only walk about 75' before I had to sit down. I decided to do the cayenne plaster, and I was SO bad I felt I had to really heat it up. I used a piece of paper/plastic drop cloth, since I was going to add a heating pad, and didn't want it to dry out or wet the pad. I cut a piece to reach from my neck to my butt, applied it and heated it up. The regular plaster usually only needs to stay in place till the heat of the cayenne dissipates.
I kept this on a while longer, and after I removed it the pain was gone.