I told you last week about my new favorite book, No More Dirty Looks: The Truth About Your Beauty Products — and the Ultimate Guide to Safe and Clean Cosmetics (Da Capo Lifelong, August 2010) by Siobhan O'Connor and Alexandra Spunt. I've been using their suggestions for DIY conditioner and hair gel with much success, so I was really excited to get a chance for a little email chat with the dynamic duo.

Read on for the back story on their awesome new book, including a DIY-Don't they encountered and their best tips for how to start greening up your personal care products — today.

PG: What inspired you guys to write No More Dirty Looks?

Alexandra: It all started because we went for a "keratin" styling treatment in West Hollywood a couple of years ago. We were thrilled with how great our hair looked—until a few weeks later when we found out that the magic ingredient in the Brazilian blowout wasn't keratin, but formaldehyde. People have even accused us of making up that story for narrative effect, but it's really true. Even the part about them giving us protective goggles! Before that, we'd never really given much thought to what was in our beauty products.

Siobhan: Which is funny, because we gave thought to just about everything else in our lives in a semi-neurotic way—that's just what happens when you're a girl and you hit your late 20s. I think no matter how much you know about how certain industries impact legislation and regulation—food and oil come to mind—it just doesn't readily click with beauty products. We needed to have an ah-ha moment. Unfortunately for us, our ah-ha moment was super expensive!

PG: How did you do your research for the book — was every week like an 8th grade sleepover with you guys trying out homemade facials and organic lipstick?

Alexandra: Oh if we lived in the same city, it most certainly would have been an endless slumber party. Alas, we kind of had to divide and conquer based on our skin, hair and preferences. With very few exceptions we tried everything ourselves.

Siobhan: It got a little gnarly at some points—when you change your face cream that often some things are bound to go wrong, and most natural deodorants quite simply don't work. But in the end we found stuff we really really love.

PG: What inspired the chapters on nutrition and lifestyle? I love your "beauty from the inside out" approach, and would love to know more about how that evolved. Seems like the good health-good skin connection gets overlooked an awful lot by the rest of the beauty industry!

Siobhan: Not to get too lofty, but we really wanted this to be a book about health, and about taking control of our own health. The beauty business sells us stuff that isn't good for us, with the promise it'll make us look better. So we want to say that when you do something good for yourself by making better choices in products and lifestyle and nutrition, you feel better and—happy surprise—you look better as well.

Alexandra: Yeah, long before we got into clean cosmetics, we loved talking and reading about food and health together. To us it just felt like you couldn't write a beauty book and ignore the importance of those choices on how you look.

PG: With all that experimenting, you must have had a few duds. Were there any epic failures along the way?

Siobhan: Oh yes! I'm an on-again off-again highlights girl, and when I heard about this new wind-powered salon that offered low-tox hair coloring, I booked it over there. As soon as the foils came off it was clear something had gone horribly wrong. Instead of the perfectly blended highlights I'd dreamed of, I looked like a freaking skunk! Two days later I was back in my old colorist's chair getting it fixed the toxic way. I'm happy to say I haven't touched it since December, and I'm pleased with how it looks.

PG: What's the best place to start if you're looking to overhaul your beauty routine, but, you know, are starting to panic?

Alexandra: Start with the products you care the least about and that cover the largest surface area. Most girls aren't as married to their body cream as their favorite lipstick—but often they're putting that cream on, head to toe, every day. Stop that today.

Siobhan: And then get rid of your shampoo. But like Alexandra says: Start slow. We recommend in the book that people replace their products as they run out. Don't empty your bathroom overnight. We didn't—and we wouldn't have felt as good about our choices if we had.

For more on swapping out your cosmetics, visit the Campaign for Safe Cosmetics and check out the No More Dirty Looks Blog. And pssst... it's going to be quite the week for clean cosmetics. Check back on Wednesday, when I'll have the full scoop for you on Annie Leonard's latest video, The Story of Cosmetics, plus some other big clean cosmetics news!