Remove the selvages and use a square ruler to square your corners. Project Linus carries and sells skip blades to use on fleece. You take the blade and place it in a 45mm rotary cutter. Using a ruler, roll the blade about .5" in from the raw edge and the blade makes small perforations to use for crocheting and edge around the fleece. You can go to www.projectlinus.org and purchase one and they accept paypal for payment.