Once those fancy Clarisonic Skin Cleansing Systems entered the beauty world, simply washing your face became hopelessly outdated.

Hands and washcloths, yawn. Hello, super soft oscillating brushes!

The original Clarisonic Sonic Skin Cleansing System, and the next generation of cleansing tools (like the new Olay Professional Pro-X Advanced Cleansing System and the DDF Revolve 400X Micro-Polishing System) are famous for gently getting rid of makeup, dirt and flaky spots without overcleansing, but they also have the potential to bring up some previously unexplored skin-care questions.

We asked superstar dermatologist Dr. Fredric Brandt to shed some light on the world of manual cleansing tools. And be sure to click through the photo gallery above for the scoop on the latest at-home cleansing gadgets and treatments.

StyleList: How often should you use a cleansing tool?

Dr. Frederic Brandt: Manual cleansers can be used in the same way that exfoliating creams can be used: once or twice a week, depending on your skin type. If you have very dry or sensitive skin you'd want to exfoliate less often -- just once every two weeks. Exfoliating once or twice a week is an essential part of your skin-care routine, but over-exfoliating is a common mistake that a lot of women make.

StyleList: What kind of cleanser should you use?

Dr. Brandt: It's best to use a more basic cleanser with a manual cleansing tool, to avoid over-exfoliating. The goal is to clean the skin without stripping it of moisture; you can also look for a cleanser made with ingredients that will provide extra benefits. Look for ingredients such as green or white tea to provide antioxidants that will help fight free radicals; aloe, grape seed and chamomile to soothe; and hyaluronic acid to hydrate.

StyleList: What should you apply -- or avoid -- after using a cleansing tool?

Dr. Brandt: Post-exfoliation is the best time to apply reparative creams, because polishing away dead skin cells prepares the skin to better absorb the active ingredients in creams. You'll get the best results by doing this before going to bed; research has found that the body releases essential repairing amino acids and protective antioxidants while at rest, which helps restore radiant, youthful skin. You should avoid using other exfoliants (like scrubs, peels and laser treatments) on the same day as you use a manual cleanser because it could cause irritation or inflammation.