Most effective: Large, flat areas similar to arms and legs. Least effective: Curved areas the same as the underarms, and cause significant trauma on the face and also other thin skinned areas. Are nonetheless in high school? If you are, look at your school district's website. https://maps.google.no/url?q=http://www.betsyrosspatterns.com/10-signs-youve-found-a-good-hair-salon-for-your-needs/