How These Teen Sisters Make $20 Million a Year Da Bomb Bath started as a hobby when Caroline and Isabel Bercaw were in middle school. Six years later, their products are sold nationwide.

Caroline and Isabel Bercaw were once obsessed with bath bombs. This was back in their middle school days, when their peers were equally obsessed with the bombs -- powdery, fist-size balls that, when dropped in a tub, release an eruption of fragrance and color and fizz. And because the Bercaw sisters were student athletes, they'd spend a lot of time soaking after practice to soothe their sore muscles. Which meant even more time with bath bombs.

And that led to a giant mess.

"A lot of times the bath bombs would stain our tub, or even our skin, which was kind of scary for us," says Caroline, now 17. So she and her older sister started experimenting at home, creating their own bath bomb recipes and adding a surprise in the center, like a small toy or piece of jewelry. They took a batch to a local art fair in Minneapolis to see if people would buy them. "We were definitely aggressive salespeople for 11- and 12-year-olds," says Isabel, now 18. "We sold out that first day and went home to make more until 1 a.m."