Mary-Kate and Ashley Olsen may have been style icons for decades with their comfy-cozy, yet cool, layers; endless supply of larger-than-life sunnies; and a seemingly innate ability to make wearing all black seem fresh and chic. But the secret to their perfectly tousled hair? It's all in the brush. The toothbrush, that is."My life-changing tip? Always carry a natural-bristle toothbrush just to clean up around the edges," celebrity hairstylist Mark Townsend, who has been working with the Olsen twins since the days of New York Minute, tells People . "I always use a natural-bristle toothbrush with extra-hold hairspray to get all those pesky hairs around the ears, the hairline in the back, get down any little flyaways on top without wrecking the hair," he explains. Because “what separates an Olsen from a woman leaving the gym is the details.”But the Olsen twins aren't the only ones taking a toothbrush to their scalp. Townsend uses the technique to get all of his clients, including Dakota Johnson and Rachel McAdams, ready for the red carpet. And the stars have learned to love the quick fix. "I have to keep about 15 to 20 toothbrushes on me at all times, because whenever I use on on a client, they ask to keep it," Townsend laughingly told the publication.Natural-bristle toothbrushes are available at most health food stores. This summer, pick one up and tame flyaways the Olsen way.