Wikipedia
Jukyeom
Jukyeom ( Korean: 죽염, Hanja: 竹鹽) is a Korean folk remedy consisting of salt roasted in bamboo. Sea salt is stuffed into bamboo tubes, and the ends plugged with mineral-rich clay; the assembly is roasted up to as many as nine times in a pine-wood kiln. The trace elements in the clay and bamboo are thought to make this form of salt more healthy. Historically, jukyeom has been used as a digestive aid, styptic, disinfectant, or dentifrice.
No systematic methodology of jukyeom manufacture, nor any analysis of its ingredients or effectiveness for any particular purpose was carried out until the publication of the book The Universe and God's Medicine by Il-hoon (In-san) Kim in 1981.