Hair Cutting TIP OF THE DAY: Refining Extensions By Maggie Mulhern March 20, 2014 | 12:28 pm EDT UpvoteClick if you like this articleOne upvote per userLog in to upvoteComments Advertisement 1 2 3 4 Kien Hoang HOW TO customize an extension to fit a fringe. 1. Take extension, measure and hold straight across. 2. Take a straight edge razor and hold at one end. 3. Gently tap the seam of the weft to separate. 4. Continue to tap down to desired length or until it separates.