I tried this method as well. To me, using the post-it is good for airbrushing panel line weathering effect since you don't need to use masking tape for such a purpose [ that would be a great waste ]. usually I don't cot off the rest of it since this cover the area which we don't want to paint. There are times when I am too lazy to do masking, I just use post-it to paint the borderline of the figure uniform and the arm. My advise, buy all sizes of post-it that is available in the store - they could become handy one way or the other. Go for it and have fun.