It's a method of tillering Badger explains over in the archives. Basically what you do is tiller the bow to brace height and then 16". Check the draw weight at 16". Now let down and draw to 17". Draw to 16" again, and check the weight. If the weight is lighter now, then check for thick/stiff spots/limbs and scrape them down, or evenly remove from the entire belly if the bow is just too heavy for the design. Let down and now draw to 18" and let down. Check it at 16". Repeat the scraping process if necessary. Normally, you won't see any real scraping until about 20-22" if you got the design down.
This way you attack the problem before they become a real source of set,