Cut in Tip: Score your ceiling first. Hold a the knife at a 45-degree angle to the wall and run the blade along the edge of the ceiling. The blade leaves a small groove in the ceiling. Now when you cut in along the top of the wall, the paintbrush bristles will slide into the groove, giving you a crisp paint line without getting paint on the ceiling. And you’ll never notice the thin line. I have more then 5 cut in videos explaining how to get perfect ceiling cut ins. Check us out on YouTube Paint Life TV.