I heard from Reb. Kanievsky a story about a bunch of girls who decided to become more Tznuis and gave up a bunch of not Tznuis stuff. They burnt it all.
In a huge shopping center there was a car filled with explosives that someone noticed and they stopped it from blowing up and a lot of people’s lives were saved.
Reb. Kanievsky heard the stories and said that it was in the zechus of the girls giving up their skirts that the bomb was caught.