I often tear off the edge pieces before putting them together. I can't remember where I heard it, but I crease every
line well before I start to sew, making it easier to fold and remove. Onion skin is better but more expensive. If your printer will take it, "deli paper" works marvelously. I've bought it my the box of 100 at a box store or a restaurant supply. It is quite thin and tears well, but strong enough that you can rip a seam if you have to. Mine is 10.5" square.