Big salt is also called coarse salt and large granular salt. Hot compress with coarse salt can improve local microcirculation, promote blood circulation and remove blood stasis, and coarse salt also has certain anti-inflammatory effect. If it is combined with far-infrared materials and traditional Chinese medicine, the effect will be more prominent. For example, our own health care center has been using coarse salt to warm compress, and the effect is particularly good. Taobao also has a lot of raw salt hot packs, among which "Five Blessingg Xiangyun Health House" is doing very well. We also have a lot of raw salt hot packs in their physical stores. You can refer to them. I can't answer your compassion for the time being. I hope you can adopt it.