Soap. The Hebrew term, borith, is a general term for any substance of cleansing qualities. As, however, it appears in Jeremiah 2:22, in contradistinction to nether, which undoubtedly means "natron" or mineral alkali, it is fair to infer that borith refers to vegetable alkali, or some kind of potash, which forms one of the usual ingredients in our soap.
Numerous plants capable of yielding alkalies, exist in Palestine, and the surrounding countries; we may notice one named, hubeibeh, (the Salsola kali of botanists), found near the Dead Sea, the ashes of which are called el-kuli, from their strong alkaline properties.