Putting a stop to impurity. These stone bottle lids and stoppers may have been used by some of Jerusalem’s most observant Jews. No stone vessels with narrow mouths have been discovered, leading author Magen to conclude that these lids and stoppers must have been used to seal pottery jugs, rather than stone vessels. According to Jewish law, pottery vessels, unlike stone vessels, can become unclean when their openings are defiled (and when they are, they must be destroyed). Thus, stone lids and stoppers, which cannot become impure, were used to keep pottery vessels—and their contents—ritually clean.